(Photo Illustration by Alex Wong/Getty Images)

This happens every year at this time. People are spending money and the counterfeiters are trying to cash in by sneaking some bills past the checkout. There are ways to spot the bad bills, and here are some tips to look for and ways you can help.

According to the Duluth Police Department there are individuals that have been passing counterfeit currency in denominations of $20.00, $50.00, and $100.00 bills. The suspects have been using the bills at commercial and retail establishments in the Twin Ports so they can get “change” back that is legitimate currency.

The Duluth Police Department is requesting that businesses dealing in cash transactions use extra care to examine these currency denominations to make sure they are genuine. Here are the serial numbers you should be looking for on the counterfeit currency:

$20.00- JK81846191A

$50.00-AD71928773A and CF06285234A

$100.00-KL25138750A

If you encounter any of these bills or other currency that appears suspicious, please call 9-1-1. Any information related to these incidents is also helpful so please take steps to check out the person that is using the counterfeit bills.