Originally Posted by
RubeRad
Also, you can buy reusable warmers that are filled with a special solution so that you can boil the pouch to cause a chemical reaction that stores potential heat energy, and then "click" an activator inside the pack and that starts a reaction that slowly releases heat back out.
While they work - technically - I've never found them particularly useful for outdoors activities. They carry a rather limited amount of heat, both in time and temperature. I've tried using them for tour skating, and more often than not found them already activated and spent when I wanted to use them.