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COLORADO SPRINGS, COLO. -- Colorado Springs Police officers are sending out a warning about counterfeit bills after a local business accepted a washed out $1 bill that had been reprinted as a $100 bill.

Officers did not say which business accepted the phony bill but said the customer washed out a real $1 bill, then reprinted it as a $100. 

Many businesses use a marking pen to validate large bills. If the ink on the bill turns gold, it's real paper. If it turns black, it's fake. However, the bill in the photo was reprinted on what was actual currency, so the pen did not detect it.

Officers said businesses need to visually inspect the bills in addition to using the pen because they can see washed out parts. Currency protections such as holograms won't be visible on fakes.