I recently accquired four HP steel cylinders that are showing various signs of surface corrosion. I removed the boots and soaked off the salt deposits and noticed some minor surface rust that I would like to address before it spreads any further. All tanks appear to be galvanized but I'm not positive, as I thought that would prevent such corrosion. What should I do to treat/remove the rust and prevent it's recurrence? I've considered naval jelly and some other chemical rust converters but I'm not sure if they are compatible with galvanized surfaces. Maybe sanding and painting? Thanks for the help.