Hello one and all .Recently bought a 2008 SunTracker 21 foot pontoon boat .Decided to try and clean up pontoons.Former owner said they were dirty when he bought it 5 years ago from original owner and he never tried to clean them up .Said they were in the water for most of the time he had it but not salt water . I Tried everything from power washing,hand cleaner and the about the only thing that worked from the water line down was SOS pads.Yes a lot of work and scrubbing .Saw on the internet to use Napa Aluminum brightener .I tried diluting it and even full strength on the under water line .Still didn't work.No idea what to try unless back to the SOS pads.Oh the brightener works well on the upper part lol . and the last pic of the sos pad and polishing.