A few years ago, while fishing with a friend of mine in the UK at Dovecote lakes in Milton Keynes we were surprised by a very bad and cold night........
our flashlights had run out, we had no candles and we were colder than hell.
I had packed some food, we were younger and foolhardier then, used to eat straight from the tin, none of this warm food up crap, so no stove also summer weight sleeping bags.
well we were below freezing and the tent was colder than a polar bears balls.... so i punched a small hole and a smaller hole also in a tin of tuna with oil, then stuffed a cotton wick in there with the aid of a knife,,,,,,, once said wick was saturated with the sunflower oil, i lit it, trimmed it, and the heat and light made the night a LOT more comfortable...... the cotton wick was the end 2" of a shoestring and the bonus was the next morning we got to eat the tuna.......... 2 for 1!
when i went for pee at 2am and came back into the tent the difference in temperature was amazing!
just thought i would share that one.....