Yep, a battery with some steel wool will do the trick, too. I've experimented with it short of actually starting a fire and man does it get hot FAST!
And speaking from a firefighter's point of view.....by all means ya gotta do what ya gotta do in an emergency, but please -- if you have to use gasoline to get a fire going, keep it to a minimum and use extreme caution. It's nasty stuff. But I'm pretty sure I'm preaching to the choir.
