Before using this product read all the instructions so you get the most out of this product. That being said here is a tip that is NOT listed on the instruction. Do NOT leave clay in this mold overnight. I have not tried it with the Air Dry Clay. So I can’t confirm that portion.
I don’t know why this happened however, I left small pieces of Sculpey III on the mold overnight and it ward and ate at the mold. Other than that I didn’t see anything wrong with this product. The instruction do say it freezer safe which is it, but if you want to release your mold without having to put it in your refrigerator. Just a dab of corn starch or flower will get that clay out.