Swipe Dri Mark’s counterfeit detection pen on a phony $20 bill and the ink comes out black, like a permanent marker. If it’s real money, the ink is gold and fades over time. The specialty ink in the ...

Just when you think you’ve seen it all, someone develops a strange new product. Consider the Counterfeit Detector Pen, which was developed by Dri Mark Products Inc. of Port Washington, N.Y. Dri Mark ...