Sanded down the plastic metal on the fuel tank. I always forget just how tough that stuff is. I used four 8"-36 grit discs to get it roughed out and about 8-10 6" DA discs in 80 grit. That stuff knocks the edge right off the sandpaper. Then I decided to strip it to bare metal and treated the rust with Ospho. Once that dries I'll shoot some epoxy primer on it for now.