#2 was the fun one though I really enjoyed doing them all. We all wore protective glasses and clothing and kept spectators at a safe viewing distance. For the steel wool shots, just take a metal kitchen whisk, stuff it full of Grade 0000 steel wool, tie a short cord (18 inches to 2 ft in length) to the whisk. Light with a grill wand and start spinning.
Contrary to what you might read and contrary to what the guy I was shooting with, I used f/11, 25-30 seconds, ISO 160 and .67EV (only because I forgot to zero it out). He shot at 5.6, 20 sec ISO 100. I went with a greater DOF so the composites had room to breathe, so to speak and to ensure I had a deeper glow factor.