I use cold water for about 30-40 minutes then I dry it and blow dry it a bit to make it warm. I have done it before and it hasn't bothered him. I used to switch it from cold water so it thaws out a bit then warm water and blow dry it. It also worked for me. I did the first thing and I have been doing it, he just hasn't been accepting it. Should I start using warm water? I was afraid to because I had heard it could cause blizzards on the mouse because it would heat up too fast and it could harm the snake. I read about it on a care sheet.