While it probably won't work on your tank, you can get your moneys' worth just fixing the little dings on your vehicles. I was able to get out a baseball dent in a hood fairly easily. Part of the trick is to work from the edges in, instead of trying to pull from the center of the dent. You may get most of it pulling from the center but that technique will leave an outline of the dent. If you work from the edges in, the repair can be almost undetectable.

The body shop told the lady $200, I spent one hour = $60. She was a very happy lady!