of what type of hot-stamp you have. I can't remember the manufacturer, but in the past, I have done just as Charles suggested, only to have the hot-stamp come off on my thumb. It's happened a couple of times, the latest being a 25 cent Silver Saddle (Las Vegas) chip. The chip was in GREAT shape with the exception of some grime on the outside edges. I didn't need to clean the hot-stamped area because it was so clean and I kept my thumb over the hot-stamp, gently cleaned the outer edges & discovered, to my dismay, that the foil had come off. Only happened two or three times...

Steve B