Breakable graphite could be useful it coloub be a material that breaks at low pressure but melts at high temp. It could form broken graphite. Broken graphite could stain wood a shiny grey colour, the same colour of the graphite. breakable graphite would not stain wood as it is a solid.
Looking back now, fallout was really stupid...
EDIT: A non-flammable acid ould be great. You could use it in conjunction with explosives, and not have to spend ages constructing an acid bomb that doesn't catch fire. Also, I think acid is WAYYYYYYY too strong
samir NUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!! *facepalm* That was SUGESTEDSUGESTEDSUGESTGUESTGUESTGEUSTEGSITEGSHUST before!!!