I have a 'tent heater' that has a filter that soaks up Coleman gasoline. You flip it to get it soaked and then light it, when the flames die down you close the cover and have a magic campfire that can kill you in an enclosed space. i have an ice shack heater that runs on gas canisters, as long as there is a good cross breeze it works well enough to keep one from freezing to death in an ice shack if there is good cross ventilation. I will never forget my first deer hunt. 14 years old, drove all the way out to the river on my Bridgestone 90 cc motorcycle at 5 a.m. I built a stick blind with burlap camo the week before, a home made doghouse. damn cold for the 1st of october. To keep from freezing, i started picking up little sticks and started a stick fire. As it got lighter I could see a group of deer about a half mile down by the river, i had to keep warm. I didn't want to go out looking for sticks, because the deer would see me, so I started picking out ones in my blind. Then a really cold breeze picked up so i built up my fire with bigger sticks from my blind, I was still shivering. With nothing left to hold the burlap up I tried using the burlap as a blanket. some yayhoo was down on the bottom field trying to stalk those deer with no cover. They all busted, jumped the Rock River and kept going. I put my burlap on the fire and ate my sandwich while the other hunters trudged up the hill all talking and yelling, while the deer bolted out of the far side of the wooded hill side. The sun was getting warmer, I got on my motorcycle went to town and bought a pair of long johns.