I just pulled the gas tank out of a '53 one tone that has been sitting in a barn since '74. Obviously rats have taken over the truck and declared a homestead inside. I believe they "[censored] and pooped" on the top of the tank for most of the years. I have sanded, used wire cone on my grinder, and sanded again. I applied Ospho and sanded that off. The top is smooth but not nearly down to original metal. I don't think it ever will get there. I bought a can of Rust Oleum "ColdGalvanized Compound to spray the tank with. IS it ok to spray this on the top over the stuff that I cant remove.

Thanks