Why can't they get rid of those counterfeit pens?

[aargh57]

OK, this has been bugging me for a while. After reading about those stupid detector pens here a long time ago I wondered why can't some consumer protection group try to get them off the market. There are class action suits that you hear about all the time for stuff that doesn't work.

I know the JREF commentaries are full of junk that doesn't work but in a way I can see why they can't be pulled from the market. For example, I saw a stupid pendant on T.V. in the pro shop the last time I went golfing that claimed it could cure your slice. Now, if you tried to get them to prove that their product worked as advertised they'd have a lot of wiggle room. They could point to some anectdotal evidence from some "pro" that believed in their product that claimed it helped cure their slice. If you tried to set up controlled experiments they could always waffle like the JREF applicants do when they fail the test saying that the test messed up the "aura" of the pendant or some other nonsense. However, a product like these stupid pens doesn't have that wiggle room. It claims when you swipe it on a bill it will turn a different color if it's counterfeit. Easy test, easy result, period. No wiggle room, no aura, nothing. It either works as advertised or it doesn't. Is it just because if you swipe it on a "counterfeit" bill that a twelve year old made on his PC with zerox paper and it changes color that it's a valid product?

Anyway, I know this is kind of a rant but it just ticks me off when I think of all the wasted real money that's being spent on these pens that aren't preventing any counterfeit money being circulated.

[robinson]

;)

Its like homeopathic medicine. It doesn't work, but it makes people feel better.

[marting]

Arghh. I saw a casino in San Diego using those iodine pens!

OTOH, Frys has this cool uV marker/led pen at checkout for about $12. I've been putting smiley faces on currency.

Might as well put a smile on tellers that use uV as a currency screen.

[aargh57]

Perhaps you meant,

;)

Its like homeopathic medicine. It doesn't work, but it makes people feel exactly the same.

[robinson]

No no no! It makes you feel like you are doing something about a problem. That makes people feel better. Sort of like praying.

[aargh57]

Robinson,

In all seriousness even homeopathic garbage has wiggle room. Those damn pens perform a function similar to a motion detection light. If a company started selling motion detector lights that didn't work when people walked in front of them people would demand their money back. The only difference here is that it's very rare to find a counterfeit bill. Even rarer when the product you're finding them with doesn't work.

I even typed in a search for these stupid things and found some "explanations" of how they work.

http://money.howstuffworks.com/question212.htm
http://www.madsci.org/posts/archives/may98/895612238.Ch.r.html

From the first link (talking about the anti-counterfeit designs already on the bill):

All of these features are nice, but no store clerk is going to stand and hold each $20 bill he or she receives up to the light to check for a security strip! It takes too long and it is not a flattering pose to strike...

What? Why not? I've seen plenty of store clerks perform this extraordinary feat. To confess, I do always make a snide comment about the unflattering pose they strike when they inspect the bill.

Next comes this gem:

The counterfeit detector pen solves the biggest counterfeiting threat today. It used to be that a counterfeiting operation used expensive presses and special inks and papers to create exact duplicates of the bills. Today, the threat is much more mundane -- people with color copiers and color printers try to create passable facsimiles of a bill. They are not trying to make an exact copy. They are trying to create something close enough that people won't notice anything if they give the bill a passing glance. These folks are not particularly careful or meticulous, so they copy or print onto normal, wood-based paper.

Am I luny or wouldn't I know the difference right off the freakin' bat if some dope gave me a home made Hewlett Packard $20 bill on normal copy paper? Wouldn't the whole texture of the bill be different? Now I don't have any experience with counterfeit money but I'd hazard to guess that the biggest threat right now isn't from Joe Schmoe making money on typical wood based paper.

I know I'm preaching to the choir here. Just ranting.

[Jeff Corey]

That link also points out that the iodine in the pen detects the starch in the wood based paper. I have been unable to locate any store here on Long Island that uses such a pen, to test their system with a fresh bill coated with spray-on starch.
I can picture the scenario.
Clerk: Ohmygod! Sir this bill is counterfeit, I have to confiscation it.
Me: No way, I just got it from an ATM. Better call the Treasury Department to arrest that machine.

[robinson]

http://forums.randi.org/showthread.php?postid=1546130#post1546130

See what Randi suggests,


heh

Also a lot of stuff about this exact same topic!!

[aargh57]

Seen it already. I did say that this was kind of a rant. I do like his suggestion but I don't have the guts to do it and have the local Barney Fife give me grief when the clerk calls him.

[clarsct]

I would starch HALF of each bill, then confuse the clerk as to why it works fine on the other half.....

I'm a bastard.

[HawkeyeMD]

I would starch HALF of each bill, then confuse the clerk as to why it works fine on the other half.....

I'm a bastard.

Oh, you're evil. :cool:

It does still piss me off when I see those things being used. Our post office the last place I did used them--so that means government money is being used to buy the useless things and then they're accepting counterfeit money on top of it.

I knew the people who worked there pretty well, and I would tell them regularly that the pens didn't work. At one point one man told me he'd talked to people at the bank next door (which I'd suggested) and they had confirmed that the pens don't work. But, he said, they were still going to use them "because training people to spot the fakes like the bankers do is too difficult".

:boggled:

So they were using something they knew didn't work to avoid training their employees to do it right. And BTW, it isn't that hard to train people to spot most fakes--every teller in the world gets that training. Sure, there are really good ones even the feds can't spot right away, but those aren't going to get caught by the stupid pen anyway.

[NeilC]

I thought the original article was a bit stupid. Just because you can produce a false positive by going out of your way to put starch on a real note doesn't mean they are not in some way useful. People have made counterfeit notes on wood based paper. It would detect those. It won't detect all forgery but nothing else will either. What is wrong with that?

[clarsct]

One must ask one's self if it is worthwhile. If the error rate is close to the success rate, then is the test worthwhile?

It is the same argument that keeps lie detectors from being used in a court of law.

It isn't only that there are false positives, it is that there are also false negatives. It passes bills that aren't real.

In real, common sense terms, it is a waste of money and time to even have them.

[bpesta22]

The problems described above are trivial compared with the real reason why these pens are absolutely worthless.

The goal is to detect counterfeit bills. If some smarty pants sprays starch on a real one, I assume that will get sorted out before the "fake" bill is destroyed, returned, whatever.

The real issue is the rarity of what these pens are trying to detect-- counterfeit bills in the money supply.

Because the base rate for fake bills has to be tiny, these pens would be worthless at a practical level, even if they were 99% accurate.

Consider:

Assume the pens are 99% accuarate-- So, for every 100 bills that test positive, 99 are really fake and one is real.

Assume the base rate for fake bills is 1 in 10,000 (I have no data on this, but the number seems conservative and reasonable, at least to me).

Assume a population of 1,000,000 bills in the money supply (just to keep the math simple).

Of these, 100 are counterfeit. The pen will find 99 of these fake bills but miss one.

However, 999,900 bills are real in the above example. The pen will make false positives on 1% of these (given the pen's accuracy of 99%).

That's 9999 false positives.

So, if we used this pen on all 1,000,000 bills in the money supply, we would get 9999 + 99 = 10,098 total positive results (i.e., results where the pen says this bill is fake).

Only 99 of these 10,098 positives though is actually a fake bill.

So, the probability the bill is fake, given that the pen says it's fake is:

99/10098 = .009

Less than 1% of the time would the pen make the right choice-- 99 outta 100 bills it says are fake are actually real, even without spraying starch on them.

A similar example is mentioned by Paulos in Innumeracy. Highly accurate tests are practically worthless when the base rate for what you're testing is really small.

I guess the research shows medical doctors rarely factor in base rate data when telling patients that their test result indicates some dreaded disease....

[bpesta22]

On the other hand, were the pen 99% accurate, it might still be useful, if the company had a second / different test it could use quickly just on those bills the pen said were fake.

Assuming the second test had decent accuracy, using the pen as the first test might be justified. The pen's value would be in dramitically limiting the number of bills that had to undergo the second test.

[NeilC]

Why do you assume you get 1% false positives? Other than smart alecs spraying notes with starch to prove a point, what makes you think a full 1% of bills colour up? I would have thought that they are more likely just to miss better made forgeries and that hardly any bills will give a positive result - much less than 1 in a 100. I would have thought that if a bill colours up then it most probably is fake.

Also think of the risk/benefit. If the pen costs £5 and it prevents the shop taking say £200 of fake bills a year then that seems like a good investment to me. Ok they would be better off checking the watermarks etc but you can't rely on cashiers to do this. It takes too long.

[bpesta22]

Why do you assume you get 1% false positives? Other than smart alecs spraying notes with starch to prove a point, what makes you think a full 1% of bills colour up? I would have thought that they are more likely just to miss better made forgeries and that hardly any bills will give a positive result - much less than 1 in a 100. I would have thought that if a bill colours up then it most probably is fake.

Also think of the risk/benefit. If the pen costs £5 and it prevents the shop taking say £200 of fake bills a year then that seems like a good investment to me. Ok they would be better off checking the watermarks etc but you can't rely on cashiers to do this. It takes too long.

I thought I was giving the pen the benefit of the doubt by assuming it was 99% accurate (which I think would be very high).

Do you think they're more accurate than that?

[Mongrel]

From my days behind the till I'd say that there's a problem if a cashier can't detect the difference between genuine banknote paper and the sort of paper that the pens are made to detect just by touch.

[NeilC]

I'm wondering why they would give false positives at all? Is starch a common contaminant of notes?

I just asked a friend who has worked in pubs etc and they never got a note that coloured. A pub takes many 100's of notes very night and he's worked in shops/pubs for years. He's seen many thousands of notes. So I believe 1% false positives to be way too high.

I think the question is how many counterfeits colour up. if they don't then it might be a waste of time. If they do then a few £ seems like a sensible investment.

[Cuddles]

I think false positives are probably not a problem here, as Splossy says. What is a problem is the cost effectiveness. Say a pen costs £1, and there are 100,000 needed in the country. Most of these pens will never see a fake note. Out of the ones that do, most fake notes will not be detected since they do not use paper with starch, most counterfeiters being clever enough to avoid this. It therefore seems very unlikely that the few notes caught will add up to £100,000, and so more money will be lost paying for the pens than will be saved by preventing fraud. Obviously these numbers are made up, but from the evidence in this and other threads, it seems that much more money is lost on useless pens than is saved by their use.

[fuelair]

No no no! It makes you feel like you are doing something about a problem. That makes people feel better. Sort of like praying.
What he said!!!

[NeilC]

I found this in a UK parliamentary report: www.parliament.uk/post/pn077.pdf

It says that the Bank of England BoE does not guarantee
that UK banknotes do not contain starch.

Furthermore, as with the UV systems, chemical coatings on ordinary paper can mask the presence of starch. Thus there is some risk of false rejection and, while the majority of counterfeits intercepted in the UK so far have not beencoated this could soon change, and false acceptance would become a problem.

So it seems that they do work at the moment but probably won't for long.

[AmateurScientist]

I wonder if some of us are missing the point. I see the real danger here to be like that of psychic surgery, only not as tragic. The chief reason psychic surgery is harmful is not because it actually harms the "patient," but because it may convince the patient in real need of actual medical care that he or she has done what is necessary, and need not seek further actual care. It is thus the missed opportunity to get genuine care that is lost do to misplaced trust in the efficacy of the bogus psychic surgery. It induces in the patient a dangerous complacency.

The counterfeit detecting pens which lack efficacy fool the users of them into believing that they can accurately detect counterfeit bills. Thus, they are lulled into a false sense of complacency that they are effectively stopping counterfeits from passing through their hands. In fact, there are numerous tests for genuineness and authenticity the U.S. Treasury built into our banknotes which can be checked in mere seconds. Checking two or three of these takes no longer than using the bogus pens, and they are actually good tests because the ribbons and watermarks and special inks are very hard to duplicate. When a clerk or merchant uses them correctly, he or she can be confident that the bill is in fact genuine or not. The pen user cannot. The pens are worthless, and they trivialize the painstaking anti-counterfeit measures the Treasury Department took to insure our currency is safe.

It's the complacency that the pens induce that is more dangerous than anything else. The users think they are accurately testing for counterfeits, when in fact they are not. Their time and effort which could have been used in good tests is wasted and lost. They don't bother to do the good tests. Thus, they are more likely to let fakes slip by.

AS

[NeilC]

You assume they generate complacency. I don't know why. Holding bills up to the light takes time and offends customers. That's why they don't do it. They wouldn't do it without the existence of pens either. If anything the pens make people aware of forgery in the first place.

And the pens do apparently work. They detect your basic photocopier forgery and if that report is to be believed they detect others too, at least until the forgers start coating their paper.

It really is nothing like fake medicine.

[ponderingturtle]

From my days behind the till I'd say that there's a problem if a cashier can't detect the difference between genuine banknote paper and the sort of paper that the pens are made to detect just by touch.

Exactly, what they do is put the focus on something other than teaching what the real features of our money are. It might have limited use with properly trained poeple with enough other tests, but it is pretty limited as there are plenty of ways that money can be contaminated with starch, like forgetting to take your money out of your pocket and then do the laundry.

It is easy to get around for counterfeiters, just buy cotton paper, so all it does is give a false sense of security.

And for the people saying it is useful, please find some endorsement from some institution saying to use it. Last time they came up I found notes from bankers saying that they where not effective and the secret service makes no official comment on them.

[bpesta22]

If anyone has more info on the pen's accuracy rate, I'd like to see it.

My google search found a range of reported accuracies. Many companies claim 100% accuracy, though, I seen one that said it was only 80% accurate.

The pen is in essence a test-- just like a paper and pencil test you take in school.

So, reliability, validity (and utility) are the only proper way to evaluate how good the test/pen is.

Accuracy is reliability. I suspect the vast majority of tests ever made have reliabilities less than 1.0.

100% accuracy is obviously the strongest claim one can make; I'm skeptical.

There's two types of mistakes the pen can make:

The false alarm (saying this bill's fake when it's actually real)

The miss (saying this bill's real when it's actually fake).

The probabilities of these mistakes are affected only by the pen's reliability / validity and the base rate for counterfeit bills in the money supply.

I couldn't find data on it, but I think it's reasonable to assume the vast majority of bills out there are real. Anyone disagree?

Given my skepticism that the pen is 100% accurate, and given the very low base rate for fake bills in the money supply, I still think my example above holds. Would be interested in hearing any counter arguments.

Oh, I did find this too!



• ARE YOU USING SPECIAL PENS TO DETECT COUNTERFEIT CURRENCY? It has
come to the attention of the Tallahassee Police Department's Financial Crimes Unit that
some local businesses may be using Currency Authentication Pens as a tool in detecting
counterfeit currency. After speaking with the U.S. Secret Service, they advised TPD they
do not recommend the use of these pens to determine authenticity of the currency. Some
of the reasons given are 1) sometimes the paper is old and the chemicals in the paper
react with the pen and will give a false positive; 2) counterfeiters will bleach dollar bills
and make them into hundred dollar bills and will appear authentic when tested with the
pen. It is the recommendation of the United States Secret Service and the Tallahassee
Police Department's Financial Crimes Unit that those wishing to use the results of these
pens should be mindful of possible false positive results and that the United States
Secret Service does not recommend their use. Pamphlets about counterfeit currency are
available through the Tallahassee Police Department's Financial Crimes Unit (850) 891-
4331.

[bpesta22]

Wow, I guess my 1 in 10000 estimate was pretty smegging accurate:

Our current money supply, genuine currency in circulation, is roughly 660 billion dollars. Out of that, the chances of getting a counterfeit note are .02 percent, or one in ten thousand.

this quote is from: Rich Stein, deputy agent in charge of the criminal division at the U.S. Secret Service,

from sciencecentral

http://www.sciencentral.com/articles/view.php3?article_id=218392063

[luchog]

1) sometimes the paper is old and the chemicals in the paper
react with the pen and will give a false positive;

Sometimes paper bills go through the wash in someone's pocket, picking up residual starch from the wash water.

[Hellbound]

Huntsman's Law #1:

No one has ever gone broke by over-estimating the stupidity of the average consumer.

[Yahzi]

Thus, they are lulled into a false sense of complacency that they are effectively stopping counterfeits from passing through their hands.
If you were a counterfeiter, what would be your first task?

Convincing people they could spot a fake, when they really couldn't.

If I were a conspiracy nut, I'd say the counterfeiters are the ones selling the pens!

:D

In fact, there are numerous tests for genuineness and authenticity the U.S. Treasury built into our banknotes which can be checked in mere seconds.
We probably spent a billion dollars of tax money developing those systems.

Only to see them rejected in favor of a magic wand.

I fear for the fate of democracy...

[Yahzi]

Holding bills up to the light takes time and offends customers.
I'm offended by the pen.

If I was gonna forge a note, I'd do a lot better job than that stupid pen could detect. Dragging the pen across a bill is insinuating I'm an incompetent idiot.

But this is America... you can't suspect someone of criminality without giving offense, but you can assume they're an incompetent moron.

:D

[ChristineR]

Well technically they do something and they do work. They turn color in the presense of starch. They don't claim to detect all counterfeits.

Really they will only detect the crudest of the crude, the kind of bill usually reserved for poorly tuned change machines. I suppose if the people using them knew how they work that would be one thing, but I'm sure that someone somewhere has accepted a suspect bill precisely because it passed the starch test.

[AmateurScientist]

You assume they generate complacency. I don't know why. Holding bills up to the light takes time and offends customers. That's why they don't do it. They wouldn't do it without the existence of pens either. If anything the pens make people aware of forgery in the first place.


I don't assume complacency. I know it for a fact. Those whom I have seen using the pens do not check any of the other quick marks for authenticity. That's exactly what being complacent means in this context.

Holding the bills up to the light to check for the embedded strip takes no more time than getting the pen out and marking the bill with it does. Furthermore, neither does turning the bill to check for the color changing ink, or looking for a watermark.

The pens are no less offensive to customers than checking for a watermark or changing ink. Indeed, they are no less offensive than writing down your driver's license number on your check when you tender a check, or verifying your available credit balance when you use a credit or debit card. Besides, checking for counterfeits isn't about not offending your customers. It's about detecting fraud and preventing loss to the merchant.

The pens don't work. They bear no relation to making people aware of possible forgeries. The anti-counterfeit measures built into our currency do that.


It really is nothing like fake medicine.

You missed my point about complacency. The point was about false belief in the efficacy of a worthless measure, and how that false reliance or belief can and does deter persons from employing a genuine test or seeking a bona fide treatment.

AS

[ponderingturtle]

Well technically they do something and they do work. They turn color in the presense of starch. They don't claim to detect all counterfeits.

Really they will only detect the crudest of the crude, the kind of bill usually reserved for poorly tuned change machines. I suppose if the people using them knew how they work that would be one thing, but I'm sure that someone somewhere has accepted a suspect bill precisely because it passed the starch test.

Exactly, the people selling them do not point out the limitations and how any counterfiet that would be caught with them would be trivial for someone who knew anything about the moneys security features to notice with out any special equipment.

[AK-Dave]

I would starch HALF of each bill, then confuse the clerk as to why it works fine on the other half.....

I'm a bastard.

You could get a starch pen or rubber stamp and write (or stamp) "NOT FAKE!" all over each bill with starch.

[JoeTheJuggler]

I lived in Ecuador when they converted to U.S. Dollars. The markers weren't a big thing because there people wouldn't accept bills with tears or ink marks of any kind--so intentionally drawing a line was pretty unheard of.

However, there was a huge market for much more expensive counterfeit detectors. They had electronic boxes that you'd feed the bill through (sort of like what's on a vending machine), and get a green light if the bill was good.

I have no idea what these things did other than separate a lot of people from their hard earned currency.

[Rat]

However, there was a huge market for much more expensive counterfeit detectors. They had electronic boxes that you'd feed the bill through (sort of like what's on a vending machine), and get a green light if the bill was good.

I have no idea what these things did other than separate a lot of people from their hard earned currency.
This is what I got last week when I went in a supermarket in Barcelona. Every note you gave them they would feed into a box, and the box would spit it out after a second or two. It rejected one of my €10 notes, though it took me a while to realize what the cashier was saying, as my Catalan isn't up to much. After looking at it for a while, I supposed the silver strip was a little worn, and that's probably what caused it. Anyway, she gave me it back, and I spent it on 80 fags (yes, yes...) down the road.

This brings me to wonder: does anyone have any idea if any nationality's notes are more or less easily faked than others'? I struggled for a couple of weeks with a Scottish fiver recently, and one of the comments made by a cashier (in Bargain Booze) when rejecting it was that it was laughably easy to fake. I didn't see how. US money has certainly improved in this respect in the last decade or so (as has British money, come to that), though I'll be pleased when they get rid of the "all the same size, all the same colour" scheme. I've had a couple of fake pound coins recently (indeed, I have one now), but coins are usually not worth bothering with. But are there countries whose national banks just can't afford, say, all the anti-fraud measures?

Just curious, of course. Nothing planned.

Cheers,
Rat.

[ponderingturtle]

This is what I got last week when I went in a supermarket in Barcelona. Every note you gave them they would feed into a box, and the box would spit it out after a second or two. It rejected one of my €10 notes, though it took me a while to realize what the cashier was saying, as my Catalan isn't up to much. After looking at it for a while, I supposed the silver strip was a little worn, and that's probably what caused it. Anyway, she gave me it back, and I spent it on 80 fags (yes, yes...) down the road.

This brings me to wonder: does anyone have any idea if any nationality's notes are more or less easily faked than others'? I struggled for a couple of weeks with a Scottish fiver recently, and one of the comments made by a cashier (in Bargain Booze) when rejecting it was that it was laughably easy to fake. I didn't see how. US money has certainly improved in this respect in the last decade or so (as has British money, come to that), though I'll be pleased when they get rid of the "all the same size, all the same colour" scheme. I've had a couple of fake pound coins recently (indeed, I have one now), but coins are usually not worth bothering with. But are there countries whose national banks just can't afford, say, all the anti-fraud measures?

Just curious, of course. Nothing planned.

Cheers,
Rat.

Well they are adding strange collors and trying to make our money look like the play money the rest of the world uses, but people are fighting it.

[aargh57]

Well technically they do something and they do work. They turn color in the presense of starch. They don't claim to detect all counterfeits.

Really they will only detect the crudest of the crude, the kind of bill usually reserved for poorly tuned change machines. I suppose if the people using them knew how they work that would be one thing, but I'm sure that someone somewhere has accepted a suspect bill precisely because it passed the starch test.

This is what they do claim (http://www.drimark.com/retail/items/smart-mony-counterfiet-detector-uscurrency-formula.html)

"While no method of counterfeit detection is perfect, Smart Money® Counterfeit Pens are an excellent deterrent for the passing of counterfeit currency, and will detect a great majority of false notes. For your protection, we recommend that this product be used in conjunction with other detection methods. The dark markings, which are produced on counterfeit bills, will not appear on recycled paper, such as newsprint or cardboard. Since counterfeiters must use high quality paper for their reproductions, this should not reduce the effectiveness of this product."

(Bold emphasis mine)

Isn't the claim in bold fraudulent? At the very least they should be required to produce some proof that their product dectects a great majority of counterfeits.

[ChristineR]

This is what they do claim (http://www.drimark.com/retail/items/smart-mony-counterfiet-detector-uscurrency-formula.html)

"While no method of counterfeit detection is perfect, Smart Money® Counterfeit Pens are an excellent deterrent for the passing of counterfeit currency, and will detect a great majority of false notes. For your protection, we recommend that this product be used in conjunction with other detection methods. The dark markings, which are produced on counterfeit bills, will not appear on recycled paper, such as newsprint or cardboard. Since counterfeiters must use high quality paper for their reproductions, this should not reduce the effectiveness of this product."

(Bold emphasis mine)

Isn't the claim in bold fraudulent? At the very least they should be required to produce some proof that their product dectects a great majority of counterfeits.

It seems fradulent to me. However I have no idea how many laser printer notes are circulated compared to the number of (say) offset printed notes. It does seem to me that no human being who was even remotely attentive could be fooled by a laser printer note, and anyone who goes to the effort of offset printing notes ought to know how to get starch-free paper.

It may be that the "vast majority" of counterfeit notes are in fact printed on starched paper, used to get four quarters out of a change machine, and then thrown out as soon as the machine is emptied.

[Yllanes]

This is what I got last week when I went in a supermarket in Barcelona. Every note you gave them they would feed into a box, and the box would spit it out after a second or two. It rejected one of my €10 notes, though it took me a while to realize what the cashier was saying, as my Catalan isn't up to much. After looking at it for a while, I supposed the silver strip was a little worn, and that's probably what caused it. Anyway, she gave me it back, and I spent it on 80 fags (yes, yes...) down the road.


In Spain major department stores chains use those detectors normally only for €50 notes and bigger. They are certified by the Bank of Spain and the European Central Bank (http://www.ecb.int/bc/banknotes/devices/testing/html/index.en.html) (the link includes test results). I've never seen anyone using 'counterfeit pens'.

[Cuddles]

I struggled for a couple of weeks with a Scottish fiver recently, and one of the comments made by a cashier (in Bargain Booze) when rejecting it was that it was laughably easy to fake.

I've never heard this claim about Scottish notes, but I see no reason to think they are less secure. The only security features in Bank of England notes that are not in Scottish ones are raised print and microlettering, which aren't generally checked for in shops anyway. The main problem with them is that most places outside Scotland don't see them very often, so they can't tell if they are fake or not because they aren't sure what they're supposed to look like. I had thought that they were accepted as legal tender, but the Bank of England website says that it is up to the parties involved whether to accept them or not.

Interestingly, the Bank of England (http://www.bankofengland.co.uk/banknotes/about/faqs.htm) also has this to say about the pens :

Can I use a “detector pen” to check that banknotes are genuine?
Simple tests reveal that some (but not all) counterfeit notes can be detected using such pens. The pens work by a chemical reaction between the pen ink and the paper. Using such pens is not a foolproof method of checking that a banknote is genuine because some counterfeits may be configured to react in the same way as genuine banknotes. Unreliability can also occur if pens are old or dirty. To check banknote authenticity retailers are reminded to check several of the security features on banknotes such as the feel of the paper and the raised print, the watermark and metallic thread. Details on the checks to make can be found in the leaflet “take a closer look” which is available free from the Bank of England.

[CurtC]

I regularly spray-starch the $100 bills I get from the bank, and sometimes even the double sawbucks, because I saw a clerk at my bank use the pen on one of those (but it wasn't starched).

Two times I've had clerks use the magic pen on $100 notes that I gave them, both times the marks were black, both times it took me a little longer to get my change, but in neither case was a single word said to me about it.

[CurtC]

I don't doubt that the pens could catch the majority of fake bills that people try to pass. Nowadays, I think it's more likely for a clerk to get handed a note that a teenager printed up at home, than to get a real high-quality counterfeit.

However, the problem with the pens is that the home-printed notes are just as easily detected by feel and sight than with the pen, and the good counterfeits aren't detected at all. It would be far more effective to take the 30 seconds and teach a clerk what a real note looks like, and the security measures that the gummint puts in them.

I think that many places that use the pens also have a UV light available as a final check. The strips placed in currency show up as different colors under UV, and the strips are in different locations, so the lights they have show where it should be for each denomination.

[MaxHardcore]

feel the power of Australian technology

http://en.wikipedia.org/wiki/Polymer_banknote

so when is America getting rid of pennies?

[aargh57]

so when is America getting rid of pennies?

When they pry them from our cold, dead, fingers.

[richardm]

I struggled for a couple of weeks with a Scottish fiver recently, and one of the comments made by a cashier (in Bargain Booze) when rejecting it was that it was laughably easy to fake. I didn't see how.

Possibly because people in England are less familiar with the way they look and feel, so counterfeiters have a slightly easier time?

[alfaniner]

I paid for a $6 purchase with a $20 bill. The cashier marked my bill. When she handed me the change of four ones and a $10 bill, I insisted she mark the ten with the pen as well. She said she already had marked it when she received it. I said "Do it anyway!" :)

[phildonnia]

I thought the original article was a bit stupid. Just because you can produce a false positive by going out of your way to put starch on a real note doesn't mean they are not in some way useful. People have made counterfeit notes on wood based paper. It would detect those. It won't detect all forgery but nothing else will either. What is wrong with that?

What's wrong is that clerks are trained to use the pen and not to use more reliable techniques.

[Inquisitive Raven]

I think that many places that use the pens also have a UV light available as a final check. The strips placed in currency show up as different colors under UV, and the strips are in different locations, so the lights they have show where it should be for each denomination.

The cash register at my shop has a UV light built into it for counterfeit detection. I've generally found it to be less than useful because you really need to shade the viewer to see many of the strips. I normally use it on $100's, but consider myself fortunate if I can barely detect a pink glow. (The strip on $100's is supposed to be red). The strips on smaller denominations is usually easier to detect.

[Rat]

Possibly because people in England are less familiar with the way they look and feel, so counterfeiters have a slightly easier time?
I had considered that, but I don't think that's what she meant. I believe that she was implying it looked like some sort of toytown money, and was inherently fakeable.

[Hamradioguy]

What's wrong is that clerks are trained to use the pen and not to use more reliable techniques.

In a past Commentary Randi wrote about my experiences with a starched 20 at the local supermarket. I got to accompany a local cop back to the police station and had to wait for a bit while he checked my "counterfit" bill and eventually said it was genuine and admitted that the pens "aren't very relaible".

But what really got me was the initial reaction of the checkout gals and the store's general manager. I kept insisting that they CLOSELY EXAMINE the bill in question. They did while alternating this with more and more pen swipes. All said how really, really good this "counterfit" bill was, and how amazing it was that it had watermarks, microprinting, threads, and all the other security features of a real bill. The manager told me he'd never ever before seen a counterfit that looked so genuine. Needless to say when I came back to the store with the cop who told him it really WAS genuine there were plenty of appologies all around.....and the store still uses the pens of course......