This is what I do:

http://boards.cannabis.com/showthread.php?t=68362

Don't use a camping stove unless it's a gas one where you can control the flame. I wouldn't attempt this using charcoal or anything 1) because you can't really control the heat, and 2) because some debris could fly into the charcoal or from the charcoal and hit the vapors from the alcohol and ignite into a massive fireball, resulting in not only personal injury but also the loss of your product.