Inedible Jewelry shop on Etsy. Mine came out ok, but hers are amazing! I'll have to try again (I wonder how she does it...).
I also stamped a few charms onto shrink plastic and came up with these, below. These stamps were from a children's stamp kit I got years ago. When I was cleaning out last month, I went through them and threw many of them away, but I'm so glad I kept these! I stamped with Staz-On inks on the shiny side of the Ruff-n-ready Shrinky Dinks, then colored on the back side with colored pencils. They're colorful and fun and almost have a 3-D effect to them.