Mine (when I get frozen) come in little individual bags. I fill up a bowl with hot water from the sink and let them thaw in that, still inside the bags. Sometimes I have to dump the water and put fresh hot water in until they are completely thawed. Then I set it on the screen top of my BPs tank and once he's ready to eat I heat it up with the hair dryer for a few minutes (making sure the head is nice and toasty ) then BAM! No more mouse