If you've seen any newer $100 bills lately, then you know that U.S. currency looks a lot fancier these days. Most of those improvements have been made to make counterfeiting bills a lot harder. But, some counterfeiters are still finding ways to make convincing money that will pass a casual eye test.
That doesn't mean you have to spend a lot of time or money to spot a counterfeit, though. There are a few simple ways you can separate fakes from the real thing. Some really good fakes have surfaced for sale online from someone calling himself "MrMouse." Here's what you need to know to avoid accepting these bogus bills in the future.
First, you've probably seen a cashier use a counterfeit detection pen that will turn a certain black on fake bills. The problem is, these don't always work. Criminals can trick these pens by using acid-free paper or bleaching smaller bills and reprinting larger ones on top of the paper. But, there are still a few tricks you can use.
"... [T]he $50 bills shipped in this package sort of failed the pen test (the fake $100 more or less passed). However, both the $50s and $100s completely flopped on the ultraviolet test. It’s too bad more businesses don’t check bills with a cheapo ultraviolet light ..."
Simply, shine a cheap ultraviolet pen light through the bill and you should see a yellow security strip to the right of the president's head. Fake bills might have a strip, but it won't look yellow under the light.
Other steps you can take
The ultraviolet light test should have you covered with any counterfeit money you might come across, but there are some more complicated tests you can run if you have the time. These ones take more time and equipment, but they're really neat because you get to see exactly how complicated our money is.
One security feature of the $20s, $50s and $100s is the use of “color shifting” ink, which makes the denomination noted in the lower right corner of the bill appear to shift in color from green to black when the bill is tilted at different angles. The fake cash ... does a so-so job mimicking that color-shifting feature, but upon closer inspection using a cheap $50 Celestron handheld digital microscope, we can see distinct differences.
There's also small spaces on the bills that contain hidden text that you can see with a microscope. On a $50, you can see the phrase "USA 50" appear a bunch of times next to the President Grant's ear. You can see "USA 100" in the left corner of a $100 bill. The same spaces on counterfeits might have lines or dots, but are unlikely to have the text, too.
You'd be surprised by all of the places you could come across counterfeit cash. Another victim might accidentally pass some off to you without knowing it. If you spot bogus bills, make sure to report them to the police immediately.