Yep, I do the same thing. They already come in a nicely sealed baggy from the petshop, so I just fill a small rubbermaid sandwich container with hot tap water, and put the mousie in the water. I just put a heavy enough glass in to weigh the bag down so the bag-o-mouse is fully submerged. Since I'm still only feeding my ball adult mice, they only take about 20 minutes to thaw out. Then by then it's 8 or 9 o'clock, so time to feed. So I just take the mouse out of the baggy, and put it under my heatlamp for 5 minutes to get nice and warm. Never had a problem feeding yet. (knock on wood)