I'll either air thaw in a zip lock bag unless I don't take one out early enough then I'll set the bag in hot water and come back to it a few hours later. Next I'll get out the $10 hair dryer I bought from Walmart and place it in front of the zip lock bags opening and blow hot air into the bag for about 10 minutes. I find the blowing of the hot air into the baggie heats them faster and more completely. I like my rats to stay dry as I use aspen bedding in the tubs and wet rats get covered in the bedding, dry rats stay cleaner.