The Peachtree City Police Department is warning local businesses and residents of counterfeit $100 bills that have been passed in Fayette County recently.

These bills can not be detected by the common “marker” test used by many businesses, police said. Residents are urged to check any money carefully before accepting it, police said.

One way to detect counterfeit bills is to hold them up to the light. That should reveal a security strip embedded in the bill that features microprinting of the letters USA, the denomination of the bill and a flag, according to the federal reserve bank.

Also visible when the bill is held up to the light is a watermark depicting the same historical person featured in the front portrait on the bill.