[tubman]

Can you tell if your problem is rust or something else (cruded up old gas)? If it's rust, I wouldn't be afraid to try it. It'll probably take at least a couple of gallons to cover the bottom of the tank (where most of the rust should be). Then stand it on each end for a day, then tilt it back for a day, forward for a day. If it comes out black, plan on doing it again.