Counterfeit detector pens

[CurtC]

A month or so ago, a man next to me at the customer service desk in my local grocery store gave them a $100 bill, which they placed on the desk and made a mark on it with a special pen they had nearby. I had already read Randi's commentary on these counterfeit detector pens, but was surprised to see one myself. I asked the lady behind the counter what the pen was, and what would happen if it said the bill was fake. She told me confidently that they would call the police, and would not in any case return the bill to the customer.

So that inspired me. Having visited the bank yesterday, with a couple of hundreds in my pocket, I decided to try Randi's idea. I sprayed them with spray starch I had in my laundry cabinet and went on my way. I figured that the pens were rare enough that I'd be putting those tainted bills into circulation for some other poor sap, but didn't expect to see the results myself.

Today I had lunch at a Schlotzky's sandwich place, and used one of the hundreds to pay. To my surprise, the clerk pulled out his detector pen. He made a mark. It was black. He made another. And then another. I was in a hurry to make it to a meeting, and didn't want any hassle, and he was in a hurry too because there was a line of customers. He showed the bill to his manager, who was working the next cash register, and the manager simply said it was OK, and I got my change and went on. If there had been more time, I would have liked to ask him what the pen was, etc., and mainly, if they use these pens, why did he simply accept my questionable bill without hesitation?

Anyway, I have another in my pocket, and I'm wondering where the first one will go in its travels.

[Underemployed]

And on a side note, you should probably put a hyphen in there next time, unless you have some general-purpose detector pens which are, in fact, counterfeit.

[/nitpick]

[Bronze Dog]

I suspect that if I ever see one of those pens, I'll go at great length about their failure and accuse the user of A) aiding counterfeiters while maintaining an appearance of plausible deniability, or B) being too much of a lazy [posterior] to spend five minutes learning how to REALLY spot a counterfeit.

[Ladewig]

I recently paid for something in Chicago with a $50 bill. The clerk held the bill under a small UV light to ensure that the embedded plastic strip showed the correct color and she then held it up to the light to check the watermark. THEN she used the detector pen. I was in too much of a hurry to ask if she ever caught a bill that passed the first two tests and failed the third.

[El_Spectre]

In an earlier life I was a cashier... we had one of those pens (where black supposedly means fake) and some joked kept putting black permanent markers in the drawer where the detector was supposed to go. Jerk!

For what it's worth, any decent cashier knows a dozen good ways to tell a mediocre fake from a real bill. Stuff that most folks don't realize, like "paper" money isn't paper, the ink is green on 1 side, black on the other, etc.

Usually you can feel a bad bill really easily if you have the touch. Of course, really good fakes can even fool banks, but it's tough to get that grade of linen to print on, etc.

The whole micro-strip and watermark were invented cuz people used to bleach real $1 bills and reprint $20s on them :)

BTW, how isn't using that marked defacting US currency and thus illegal?

[Anti_Hypeman]

Its not rare I see those pens everywhere. I once had a five spot tested at a gas station. Anywhere I use a 20 it gets marked one of these days when I have time to kill I will spray one of them.

[Bronze Dog]

Usually you can feel a bad bill really easily if you have the touch. Of course, really good fakes can even fool banks, but it's tough to get that grade of linen to print on, etc.
One of the big reasons I heard counterfeiters don't use the cheap, starchy paper the pens detect: The typical American doesn't really look at his money, but he does feel it. Often, the average American's first warning sign of a bad bill is how it feels. That's also one of the reasons they turned to bleaching 1s: They feel right, and most Americans would never bother looking at the strip or the watermark.

[Ladewig]

. Stuff that most folks don't realize, like "paper" money isn't paper,

It isn't? What is it then?

[El_Spectre]

It isn't? What is it then?
It's a polyester based cloth, the exact blend is guarded and it's supposedly very difficult to get.

Consider how many more folds and wet/dry cycles a bill will survive vs. a piece of paper, if it helps.

[Ladewig]

It's a polyester based cloth, the exact blend is guarded and it's supposedly very difficult to get.

Consider how many more folds and wet/dry cycles a bill will survive vs. a piece of paper, if it helps.

Would you provide a citation for that? I am having a hard time believing it.

[Neutiquam Erro]

Would you provide a citation for that? I am having a hard time believing it.

The Bureau of Engraving and Printing refers to it as "paper," but describes its wood-product-free composition thusly:

Currency paper is composed of 25% linen and 75% cotton. Red and blue synthetic fibers of various lengths are distributed evenly throughout the paper. Prior to World War I the fibers were made of silk.

http://www.moneyfactory.com/document.cfm/18/106

[rebecca]

I suspect that if I ever see one of those pens, I'll go at great length about their failure and accuse the user of A) aiding counterfeiters while maintaining an appearance of plausible deniability, or B) being too much of a lazy [posterior] to spend five minutes learning how to REALLY spot a counterfeit.

And I'm sure that the poor kid at the register who has only been trained by his manager to do this or else get $100 taken out of his paycheck will thank you properly for increasing his knowledge for the day.

[alfaniner]

I already tried arguing with a video store clerk about the uselessness of these pens -- he refused to budge or even acknowledge it. I decided not to waste any more of my time arguing with a video store clerk.

I thought about doing the spray starch thing but can see how that might escalate into a whole police/delay thing, and would not be worth the effort.

But just now I thought -- make a stencil and spray some thin lines on it. Imagine their expression when the marks come out tiger-striped. Or stencil the word "REAL" on it, then have them go over the entire bill until it appears.

Personally I hate to see a brand-new bill get marks put on it.

[rebecca]

I find this subject incredibly interesting, for a number of reasons.

This is a topic that directly affects people in a way that will get their attention -- after all, it's their money. The pens are well-known; most people have seen or used them on a number of occasions. It's easy to explain the science behind why these pens are wrong, and it's easy to debunk.

So why are so many skeptics apparently making the mistake of missing an easy opportunity to enlighten someone? Randi's idea of taking money from the bank, spraying it, and returning it is clever, and rude, and worthless. People will take these bills, and eventually someone will get "caught" with one. Maybe they'll be let go because everyone is in a hurry. Maybe they'll have their cash taken. Maybe they'll get in a big argument, and at the end of the argument -- what? They decide the pens never work? No, they realize the pen somehow didn't work on their bill, or maybe they decide they had been given a counterfeit bill at some point, but never do they understand what has happened.

What about the tactic of scolding a cashier? Does anyone believe this will help? These people have been trained to do something. How should they know it's bunk, unless someone kindly tells them? So educate them, if you want. But do it nicely: "Hey, do you know how those things work? They actually detect starch, which is unreliable because bla bla bla . . . " People like hearing about scams and frauds, so tell them if they'll listen.

You shouldn't, however, expect that to mean the cashier won't do it next time. You know why? Because if a manager counting down the register at the end of the night finds a counterfeit $100 bill, the first thing he's going to do is confront the cashier. The cashier had better be able to point to a "cover your ass" mark on the bill, or he's in big trouble. Is it right? No. Fair? Nope. Effective? No. So talk to a manager. That's how store policy gets changed, not by harassing some peon punching buttons at the counter.

[Soapy Sam]

Also, don't forget. If there's a dud $100 in there at shift end, there's a good chance it was put there by the clerk himself. At the very least he will be assumed to be an accomplice of the person who passed the note.
He may not only lose his job, but find himself in jail. He loses nothing by using the pen. And he gets to make the smartasses wait in line a minute longer.

[bpesta22]

Even worse-- the pens could be 99% accurate and still be worthless.

The base rate for counterfeit bills in the money supply has to be real tiny (does 1 in 10,000 bills seem like a reasonable estimate?)

If so, and we tested the pen on 1,000,000 randomly selected bills, we'd get this:

of the 100 bills that are counterfeit:

the pen would correctly ID 99 of em, and miss just one.

of the 999900 good bills, the pen would mistakenly claim that 1% of those are fake-- that's 9999 false alarms.

So, the probability that the bill is actually fake, even though this pen's 99% accuracy says the bill is fake would be

99 / 10098 = .01%

100 to one odds that the bill was real, even though the 99% accurate pen said it was fake!

[Bronze Dog]

The whole accusation thing of mine is more emotive. There's just something about this scam that pushes a previously unknown button in me. I type about a lot of things I'd never do in meatspace. Like laughing derisively at IDers.

I'd probably go along the lines of "You realize that pen's a scam, right?" If the clerk didn't know, I'd ask to talk to the manager.

[CurtC]

I wonder about how many fake bills are out there, and I wonder what proportion of those fakes are good counterfeits vs. something a teenager printed on copier paper. I have to think that a bill printed on copier paper (which these pens can detect) would be pretty obvious to any clerk even without a pen that it's fake. When we got a good color copier at my office a few years ago, I tried it on a couple of bills, and they look pretty good at first glance, but they feel completely different from bills, and on closer inspection it's pretty obvious.

So if the stores are trying to catch home-printed bills, the pens would work, but they're unnecessary, and if you're worried about professionally counterfieted stuff, then pens won't indicate them.

[Bronze Dog]

In short: Unnecessary for low-quality counterfeits, useless for high-quality.

Taking five minutes to read one of those pamphlets that sprung up everywhere when the government changed all the money: Will cover just about everything except the highest quality counterfeits.

[alfaniner]

FYI, I understand that in the US it is a felony even to copy a bill at the actual size. It has to be copied at minimum 150% enlargement or at a maximum 50% reduction (I think.)

[CurtC]

Yes, when I copied those bills, it was a felony. Interestingly, when we got a later model color copier, it refused to copy currency. The display showed a little currency symbol with a circle around it and a slash through it.

[Bronze Dog]

Yes, when I copied those bills, it was a felony. Interestingly, when we got a later model color copier, it refused to copy currency. The display showed a little currency symbol with a circle around it and a slash through it.
Well, that's interesting. Obviously a government conspiracy to prevent me from, uh...





...expressing myself creatively by trading my photoshop artwork for goods and services.

[El_Spectre]

Yes, when I copied those bills, it was a felony. Interestingly, when we got a later model color copier, it refused to copy currency. The display showed a little currency symbol with a circle around it and a slash through it.

Yeah, that's being built into a lot of stuff... I believe the law only applies if you're trying to make high quality copies... really low res or B&W is OK (I think).

Here's some more info:
http://www.moneyfactory.gov/document.cfm/18/117

I couldn't find a link, but I recall that the gov used to also provide good looking (but not good enough for conterfeiting) images in a digital format, so you wouldn't need to scan 'em.

[El_Spectre]

Ooh, I want a $500 bill!

http://www.moneyfactory.gov/section.cfm/5/61

[Dr. Imago]

I'd probably go along the lines of "You realize that pen's a scam, right?" If the clerk didn't know, I'd ask to talk to the manager.

I think we've got this all wrong.

Forget the starch. Forget trying to reason with someone who doesn't have enough motivation or intelligence not to be a cashier in a convenience store. No, what you should do when they grab the pen and put a mark on it is inform them that they've just committed a federal crime.

Section 333. Mutilation of national bank obligations

Whoever mutilates, cuts, defaces, disfigures, or perforates, or
unites or cements together, or does any other thing to any bank
bill, draft, note, or other evidence of debt issued by any national
banking association, or Federal Reserve bank, or the Federal
Reserve System, with intent to render such bank bill, draft, note,
or other evidence of debt unfit to be reissued, shall be fined
under this title or imprisoned not more than six months, or both.

http ://caselaw.lp.findlaw.com/casecode/uscodes/18/parts/i/chapters/17/sections/section_333.html

This is clearly an example of defacing federal property and, in my opinion, makes them unfit to be re-issued. When the rocket scientist behind the counter puts a mark on the bill, you should call the Secret Service and request prosecution to the fullest extent of the law.

-Dr. Imago

[El_Spectre]

I think we've got this all wrong.
Forget the starch. Forget trying to reason with someone who doesn't have enough motivation or intelligence not to be a cashier in a convenience store. No, what you should do when they grab the pen and put a mark on it is inform them that they've just committed a federal crime.


http ://caselaw.lp.findlaw.com/casecode/uscodes/18/parts/i/chapters/17/sections/section_333.html

This is clearly an example of defacing federal property and, in my opinion, makes them unfit to be re-issued. When the rocket scientist behind the counter puts a mark on the bill, you should call the Secret Service and request prosecution to the fullest extent of the law.

-Dr. Imago

1) I have both intelligence and motivation. I've also been a clerk. Shockingly, I wasn't able to get that job at CERN when I was 19... get over thyself.
2) A small mark on the bill doesn't render it unusable. If a tiny corner is torn off, is the bill unusable? Nope.

[Dr. Imago]

1) I have both intelligence and motivation. I've also been a clerk. Shockingly, I wasn't able to get that job at CERN when I was 19... get over thyself.
2) A small mark on the bill doesn't render it unusable. If a tiny corner is torn off, is the bill unusable? Nope.

Humor. Look it up.

-Dr. Imago

[Ladewig]

This is clearly an example of defacing federal property and, in my opinion, makes them unfit to be re-issued. When the rocket scientist behind the counter puts a mark on the bill, you should call the Secret Service and request prosecution to the fullest extent of the law.

-Dr. Imago

You do realize that the mark fades away in a matter of hours, don't you?

[El_Spectre]

Humor. Look it up.

-Dr. Imago

It's amazing how being a jerk transmogrifies into "humor" when people are called on it :)

[Just thinking]

A small mark on the bill doesn't render it unusable. If a tiny corner is torn off, is the bill unusable? Nope.

I believe that if at least 60% of the bill is present with only one serial number showing (regardless of denomination) it still has full face value. And if 50% is present with only one serial number showing, it has 50% of it's face value. But, (and of this I'm not so sure) if both copies of the serial number are present and match, you get full face value regardless of percentage present.

The above applies at banks, which means they probably check with the Feds first -- most places won't accept bills with even 10% missing.

Oh, and less than 50% without both matching serial numbers -- nada, zilch, squat.

[El_Spectre]

I believe that if at least 60% of the bill is present with only one serial number showing (regardless of denomination) it still has full face value. And if 50% is present with only one serial number showing, it has 50% of it's face value. But, (and of this I'm not so sure) if both copies of the serial number are present and match, you get full face value regardless of percentage present.

The above applies at banks, which means they probably check with the Feds first -- most places won't accept bills with even 10% missing.

Oh, and less than 50% without both matching serial numbers -- nada, zilch, squat.

More info here: http://www.moneyfactory.gov/section.cfm/8/39

[Dr. Imago]

It's amazing how being a jerk transmogrifies into "humor" when people are called on it :)

It's amazing how people can completely get the wrong inference and tone from a clearly sarcastic bit of writing.

[Dr. Imago]

... or maybe you just completely missed the smiley face (that is still now and always was) there at the top of my post the first time you read it. :confused:

[El_Spectre]

... or maybe you just completely missed the smiley face (that is still now and always was) there at the top of my post the first time you read it. :confused:


Yeah, ok...

[DrMatt]

USA money is printed on white rag with red and blue threads running through it. Higher denominations all have watermarks, laser reflection parts, microprinting that you can resolve with a strong magnifying glass (but which most copying processes cannot fake), and ultraviolet-glowing stripes. Any given bill might or might not have been exposed to starch. Starch-free stock includes newsprint, some recycled paprs, etc. Okay, you all knew this already, presumably...

[Mojo]

The Bureau of Engraving and Printing refers to it as "paper," but describes its wood-product-free composition thusly: Currency paper is composed of 25% linen and 75% cotton. Red and blue synthetic fibers of various lengths are distributed evenly throughout the paper. Prior to World War I the fibers were made of silk. That's still paper, just a better quality of paper than that made from wood pulp. Historical note: wood-based paper didn't really start to be made until the nineteenth century; before that most paper was made from rags. For this reason nineteenth century books often present conservation problems that earlier books don't, because wood pulp paper is acidic, so that it tends to disintegrate.