Stain removal?

[hallburg]

What Barkeeper has in it and some other products is a small amount of Oxalic acid. It removes rust stains and everything else except heavy grease. Typically used for cedar deck and fence bleaching. You can find it on the internet. I got a 5 gallon bucket several years ago. Mix a couple teaspoons in a sprayer bottle of water, spray your boat wait a few minutes and rinse off. Takes off all stains & grime, everything. A little caustic, don't breath the spray, use rubber gloves rinse everything well. Cleans my boat in a few minutes every year with no work. Will remove some wax also, gets it clean down to bare gel-coat, then re-wax. Hope this helps. I am a new seacraft owner bought, bought a 23 Tsunami project yesterday.