I would NOT put my thumb directly on the hot-stamp. I used to do that until a portion of the foil lifted onto my thumb. First time was a 24 cent Silver Saddle -- hot stamped looked great but just wanted to tidy-up the edges -- MISTAKE as my thumb ended up with as much gold foil as the chip. Same thing happened a month or so later. Now, I tear off a small piece of paper towel & put it under my thumb just in case.

Steve B