I've used a number of things in a pinch. PAM is the key, really. Paper towels, paper sacks, even the cardboard off of cereal boxes. If it's paper and/or wood based, it is a target at those times. Even so, you're never in a real jam so long as you make one of these, which we used to make/bring for scout camps. They last a real long frigging time, and so easy to refill. Just corrugated cardboard, parrafin and a can (like a tuna can)...
Or if you just want to spend some money and have some fun, those Weber cubes are frigging AWESOME!! Sam's Club sells Sterno Cans to heat foodservice trays. Those will work. So will a friggin arrangement of tealight candles if you need.
I guess I have never just held a lighter to the underside of a chimney though. That would also work if yoou are patient and have the right kind of lighter to go that long.
Or just get a weedburner.
Or use your gasser.
DO NOT put your chimney over your stove though. I'm sure you already know that, but in case you're getting ideas.
Blowtorches...
OK, I'll stop now.
