I hear that if you have a dent in your door, you can just open the door, put a shotgun on the inside of the door even with the dent, and pull the trigger. The BB's should do the trick!!
Seriously though, I have to agree with Mass Stang. Even though this guy might not know jack about sh**, you should be able to look at a piece of sandpaper and see that it is going to trash the paint. I mean, come on man, that is just something a 3 year old would do, and we have to drive on the same roads as idiots like this.
Caymon