Well, Jeremiah, the dry ice technique was explained to me by a native West Texan thusly: Park the car outside in the hot sun all day (preferably at the height of summer). In the late afternoon -- when the body is good and hot -- put a piece of dry ice on the dent. Theoretically, the metal will contract so quickly that the dent pops right out. I've never tried it myself and the guy who told me that drinks quite a bit. Hence, I think it might be something that good ol' boys in the Permian Basin tell each other to kill time between rounds.