I can not put in oven - I e-mailed Bramble Berry. She suggested I use a heating pad.. which I saw at dollar store for 10.00 I think I will get because I have no Idea where mine is..
the heating pads you can buy today turn off after about an hour
what i do now is heat up my rice filled sacks (that I use for my back!) or a couple of bricks and put them in a cooler (lined with a towel first). then I put a towel on top, put the soap molds in, and then a towel over top again. put on the lid.