So I have my car stripped down to just a few parts left. I wanna do as much as I can before i ship her into the body shop for paint, Im thinking about renting a sandblaster and compressor. My biggest problem is the undercoating-sticky tar substance that only a propane torch will remove on the underside of the car. I wanna get the whole car to bare metal and work especially on the underside because i suspect a few problem spots that where just coated over with that goop. I know sand will build up alot of heat and warp the metal like the roof, so should i use sand on the bottom and then that nutshell stuff on the body panels?