Interesting. That's definitely something to keep in mind of you are going to leave the stamp on.
Did you notice if any of the colored foil stamps had the color lifted, leaving silver beneath? I have a yellow Star Valk that has a green foil stamp - The first day I got it, it landed in a small creek. When I dried it off, some of the green started to sluff off, leaving the stamp silver beneath.
"I don't know who started it and I don't give a f***. The one thing I do know is that we did it harder, we did it faster, and we definitely did it with more love, baby. You can't take that away from us." - Stevo, SLC Punk