I know you may warm the mouse in water, but some of my snakes would not eat them wet, which is where the blow dryer comes in. If you don't want to whack them you could also get dry ice and put it in a small styrofoam cup with a coffee top lid, and put it in a cooler, or rubber-maid container that it fits in, then put the mouse in the cooler with the cup and close the lid and wait about 15-30 minutes. What happens is they will fall unconscious and die in their sleep. It is better that whacking.