Wood bleach is powdered oxalic acid. Mix it to the strength you need. Buy at any hardware store. Cheap. Rinse trailer very well especially aluminum.
84’ 18 Privateer
08’ Yamaha 90
2011 Aluminum Trailer
There are always greater fish than you have caught, always the lure of greater task and achievement, always the inspiration to seek, to endure, to find.
Roger that. I found it pretty cheap at Lowes once. In fact, I remember now that some of us posted a thread on it a couple of years ago on this site, and I think I posted a link to the oxalic acid (wood bleach) at Lowes. It might still be there.
I didn’t think about the trailer. Man, putting acid on aluminum (or steel) is a pretty bad idea. That may be a reason to try the ascorbic acid (not nearly as harsh).
Gotcha Covered,
Lee Strickland
Strickland Marine Insurance, Inc.
843-795-1000 / 800-446-1862
The trick is to use it once. Then wax the hull with a really good marine grade wax. Once your done waxing…Do it again to have two coats of wax. I did my stern and one side of my boat last year. (got lazy) One trip out and the non waxed side had a stain. The stern and other side were stain-less.
84’ 18 Privateer
08’ Yamaha 90
2011 Aluminum Trailer
There are always greater fish than you have caught, always the lure of greater task and achievement, always the inspiration to seek, to endure, to find.
BKF…and wear gloves 
miss’n fish’n
212 SEAHUNT CC
Sea Squirt 16