Today the blasting media has changed to Walnut Shells, Glass Beads and other "cleaner abrasives." If you are near a lg city, look in the yellow pages for Sandblasting Rental", then use their equipment, buy the media of your choice.
POR-15 is an amazing product. If its just scaled rust and not flaking off in chunks you can use it. If you have small pinholes that's fine too. I used the product on the floor pans of a 1971 k5 Blazer and it worked very well. I had no holes and coated both sides of the pan. You can't chisel the stuff off once its cured.
I have also used it to paint sub frames and drive line parts of various cars. Its extremely tough stuff.
Depends on the level of rustation, dude! If it's cancerous (rotted thru), it will have to be cut out and replaced. If not, scrape, wire wheel and paint w/ Naval Jelly, a rust inhibitor, and shoot on a good coat of primer.
Sand paper, sand blast. Usually you will to use abrasives.
