Three brothers I know.....they were raised in a big junk yard by their dad. One of them has a popular body shop now.......but years ago I was with his older brother Jimmy taking a windshield out, and the body shop brother was up in the wheel well of a truck he was getting ready to sell. He had cardboard, making tape, and spray cans of undercoating. As we finished up, and was carrying the windshield past where he was working, Jimmy says......fixing up another rust free truck are ya?
Reminds me a place I worked at in high school, tow company, used car lot, junk yard, police impound yard, service center, all rolled into one.
Was owned and ran by a ex cop, he'd get a used truck in, first thing we were instructed to do, was put it on a lift, knock all the loose dirt and crud off underside of truck, with a air hose or brushes as fast as possible, then rattle can semi gloss the entire underside of the truck, and the wheel wells. Change the oil if it was black.
Any rust holes on the lower fenders or doors, bondo the holes shut, mask off the truck lower body line down, and rattle can it, give a two tone looking paint job. Out the door it went on to the car lot. Big rust holes we used chicken wire and or card board, then bondo, grind it down and rattle can it. Faster you could get it done the happier the owner was. He had cases and cases and cases of black rattle can spray paint in the shop. He must of got a deal on it somewhere.
Lot of sketchy stuff went down there, bunch of high school kids fixing trucks..... Wally the owner would come out of his office and give us a five minute run down / walk around of how & what he wanted fixed, when we drug the next yard truck in, it was always fastest way to fix it and get it on the lot for sale. There was always 10-15 project trucks in the junk yard waiting to be worked on.