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Counterfeit detector pens

CurtC

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CurtC
Joined
Aug 4, 2001
Messages
4,785
Location
Dallas, TX
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.
 
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]
 
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.
 
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.
 
Never trust those pens

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?
 
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.
 
El_Spectre said:
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.
Click to expand...
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 said:
It isn't? What is it then?
Click to expand...
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.
 
El_Spectre said:
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.
Click to expand...

Would you provide a citation for that? I am having a hard time believing it.
 
Ladewig said:
Would you provide a citation for that? I am having a hard time believing it.
Click to expand...

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.
Click to expand...

http://www.moneyfactory.com/document.cfm/18/106
 
BronzeDog said:
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.
Click to expand...

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.
 
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.
 
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.
 
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.
 
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!
 
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.
 
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.
 
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.
 
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.)
 
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