I use a small wooden cabinet with a 100 watt light bulb in it. After it's been on a while it will keep the cabinet around 125 degrees. Wrap the gun and stick it in the holster and put it in the cabinet. I usually leave it in 30 minutes to a hour. Take the gun out and put the holster back in for a while.
In the summer you can put them in a closed vehicle, just like a oven.