I don't like using a utility knife on my cutting mat. I have a rotary cutter designated strictly for other crafts. how can the safety pins come out if they are secured like they're suppose to be. That's OK, I don't like the safety pins and don't feel like purchasing that little tool that helps secure the safety pin. BUT I do use foam. I have craft/makeup sponges, I've cut down. I can get them at the dollar stores.