If you keep your tank full all the time, then the gas will keep the moisture off the metal. If not, then I would say to coat it with one of those sealers. Also, to reduce contamination, add an in-line fuel filter below the petcock valve.After using electrolysis, I wouldnt have to coat the inside? Its a solid tank and not very much rust on the inside. I just want to stop the rust completely so it wont clog up the carb.