Counterfeit bills are circulating a Colorado community at what police are calling an all time high.

Authorities say it’s happening at convenience stores and even at garage sales in Pueblo. Many of the criminals are using at technique called washing where they’ll use a chemical to strip the ink off a one dollar bill and re-reprint it as a 100 dollar bill. But if the clerk doesn’t catch the bogus bills you could get it back as change. Just last week one employee at the Family Dollar store spotted a counterfeit bill.

“He handed me the ten dollar bill and as soon as I felt it, it just didn’t feel right. So I kind of looked at him and grabbed the marker and it turned black so I figured it wasn’t real,” Bonnie Johnson said.

Police say it’s best to use the counterfeit ID pen to determine if the bill is real or fake. You can also check for the water mark and security strip. If a person is caught they face felony charges for forgery.