"If it's a $20 bill, the chances of it being counterfeit are much greater than if it's a 50 or 100," said Alamo Sheriff's Department Cpl. Elmer Glasser.
The most common form of counterfeiting, he said, is when people take $5 bills and alter them to look like 20s.
Danville police Chief Chris Wenzel said counterfeiting is one of the issues that businesses need to be aware of. At last Thursday's Discover Danville Association meeting police handed out pamphlets on how businesses can avoid falling victim to such crimes.
Wenzel said that while counterfeiting does happen in the area, it's not widespread. Incidents of the crime are "streaky" and inconsistent. Counterfeiting season is in the spring and summertime, when folks start to do more shopping, he said.
When a counterfeit bill is passed, the shop owner loses out not only because they've just given away a product for free, but also because they often give the "customer" change in cash for the fake money.
Wenzel said employees usually don't catch the fake bills right away but will notice later when they're counting the cash from the day. Then they have to think back to try and figure out who gave it to them.
And sometimes the bills aren't caught at the store level at all. Glasser said that $20 bills or smaller in particular aren't usually discovered until they reach the bank.
Business owners and managers will usually educate their employees about how to spot counterfeit money. One popular method is to use a marker, called a counterfeit bill pen.
"They're trained to scratch the bill - run the pen across the face - and if the bill is counterfeit it turns one color, and if it's real it turns another color," said Glasser.
Another technique is to look at the watermark on each bill. When the bill is held up to a light source, the watermark should match the picture on the front of the bill.
"If the face doesn't match the watermark or the watermark doesn't match the face, it's counterfeit," said Glasser.
The Treasury Department is constantly coming out with new bills, redesigned with additional features that aim to make them harder to replicate.
Wenzel said these new features make it about 10 times harder to make counterfeit money nowadays than it used to be. But even still, it's not difficult to do, he said.
"I think the federal government has made every effort to make the bill harder to photocopy or counterfeit," said Wenzel. "But there are still ways around what they've established."
Which doesn't mean people should try it at home: Counterfeiting is a very serious crime. It's considered forgery, a state offense, and moreover there's a separate federal offense for counterfeiting. Both crimes are felonies.
Glasser advised people who think they have accidentally been given a fake bill to go to their local bank to make sure. Retailers who come across fake bills should keep them, try not to touch them, and call their local law enforcement.
He said it's important that each and every counterfeit crime is reported, so that police can track patterns.
Danville police discussed counterfeiting at a crime prevention meeting held a few weeks ago. Police are trying to take a proactive approach to crime prevention, by helping educate the public about various crimes in the area, Wenzell said.