Shrink foil is popular for making keyrings, badges, original earrings or smaller decorations. First you paint a design onto the foil, which then shrinks to roughly 1/2 to 1/3 of its original size and becomes firmer when heated in the oven (smaller creations can be heated with a hot air gun). For working with shrink foil, we recommend using Posca brand markers, and you can finish the completed piece with clear varnish or cast it in crystal resin.