Counterfeit $20s turn up Eugene

EUGENE, Ore. - Several hundred dollars worth of counterfeit $20 bills were found circulating in Eugene, police said.

"While the total amount of fraudulent money didn't exceed more than several hundred dollars, investigators believe it serves as a good reminder to brush up on your money authentication skills," police said.

Merchants who get a bum bill are out that amount of money. Counterfeit bills cannot be exchanged for real ones.

The U.S. Bureau of Engraving and Printing embeds security measures in each bill that make it possible to identify counterfeit bills.

From colors to printing to artwork, bills are made difficult to fake - and easy to ID as legit.

INTERACTIVE: Explore security measures of U.S. currency

Police said $20 bills are the most popular bills to counterfeit because they are easier to pass than larger denominations. Smaller bills - even counterfeit $1 bills - are not unheard of.

Last summer, police in southern Oregon seized $200 worth of counterfeit $50s.