It appears to be from oak leavesWhat is the stain?
This stuff will clean virtually any stain. It is a very good product and it will not harm your boat. As said above, wax afterwards.Bar Keepers Friend-I'm pretty sure it's just oxalic acid as well. Just make sure you re wax it after you use this stuff.
Absolutely. Forgot to mention that. I got it all over my old trailer and it wasn't pretty. Fortunately the trailer was almost at the end of it's life anyway.This stuff will clean virtually any stain. It is a very good product and it will not harm your boat. As said above, wax afterwards.
HOWEVER - do not let this (oxalic acid) touch your GALVANIZED trailer. It will start to eat it immediately and it will not quit even after you think you sprayed it off.
^This^ I use Roll Off, Magic Eraser and this when I first got my current boat. Starbrite FSR is the most effective on removing stubborn stains, including rust.The Starbrite Fiberglass Stain Remover is some good stuff. Let is soak a few minutes