Either that or just keep a few cheap rattle cans of paint in the shop and spray the frame from time to time. I had a lot of luck with those flap discs made of sandpaper that attach to grinders. They're like $5 apiece, but they burn through the rust FAST. I chose cheap-o spray paint colors so if she gets all messed up, out with the spray cans and bingo!-good as new.