When I first bought my 1969 cadillac, it was fresh out of storage of 15+ years. It had rust, but that light stubborn kind. The secret the previous owner used was actually a similiar form of what power sport vehicles use to protect their many neutral or bare metal parts. I used a scotch-brite and pb blaster. It really works on pulleys,fan blades, ac compressors, and many cast part housings. DO NOT use it to clean dirt off firewall, engine, or body tags as you will erase whatever info may be painted on.