I'd just use the grill...just stick a twig in there, pull it out, light some leafs and set it on there...
Or WD-40...the best was when I took a peice of erector set, and set it across the gap beween 2 bricks...then put leafs under the erector set peice, the car(or cars) on top, lit the leafs, and then used the WD-40 to really heat things up. You can use WD-40 as a blow torch too lol, just spray at the fire, and then lift the can while still spraying, you end up with a fireball in mid air, and you can hold it there for, well, ever. And so I had this fire going, and I would take the victom car, put it on a brick next to one of the other bricks, and zoom it across the "Bridge of Burnage"(corny, but that was the name), sometimes the wheels would just melt and the car would be stuck, in the middle of the bridge, and burned untill we(me and my bro) could get it out with a stick or something.
Last time either of us burned stuff was last week lol...my bro had to get ready for his graduation seremony, and closed his door, and took out a lighter(hell if I know where he got it, he doesn't smoke or anything...just to burn stuff I guess...)and began to torch a car...then mom opened the door, he threw the evidence into the bath tub, and my mom found it ofcourse, and the room stunk...mom threw the contriband away(I was going to retrieve the car from the trash...but I didn't get a chance to, and that's desgusting... He really didn't get into trouble, just the stuff was thrown away.
At times we are just nuts...pretty funny times though.