Kawaii Flexible Mini Molds are so Convenient and Super Easy to use. You can use them with ALL types of craft clays (Polymer Oven Bake Clays, Resin, Paper, Air Dry, etc.) and even with acrylics for making nail art with no stuck molds. Leave your air dry clays in as long is you like and then pop them out with no problems and no residue in your great molds. All Kawaii Flexible Mini Molds are Non-Stick and Non-Toxic.