Sandblasters?

For small stuff you really need a blasting cabinet. You can buy one fairly cheap at Harbour Freight, or if you feel industrious you can build one. Use Google to search for plans.

For larger stuff you will need a BIG compressor and LOTS of media. I would not use sand on any body panels. The sand acts like tiny hammers and will stretch and distort the thin metal. You would be better off getting a DA sander and/or using chemical strippers for body panels.