How do i get this out?

gman546

Seaman Apprentice
Joined
Aug 21, 2024
Messages
46
No matter what i do i cant get these what look like to be either spider poop or bird poop marks out of my gel coat. i sit there with marine spray 9 over and over and its like its baked into the white gellcoat. Lake erie. do others have this issue? what do you do?
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Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
53,102
get some oxalic acid (wood bleach) and mix it up

most hull cleaners have oxalic acid.
most toilet bowl cleaner have oxalic acid.
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
19,450
I keep a bag of oxalic acid on the shelf for cleaning mineral and iron stains.
 

DeepCMark58A

Captain
Joined
Aug 17, 2015
Messages
3,502
Go to $ general buy toilet bowl cleaner, just like a toilet apply and let soak may take two applications but the stains will be gone.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
53,102
how is that acid in the water from overspray?
Oxalic Acid is made from Rhubarb.

its a naturally occurring acid, just like oranges and tomatoes

Go to $ general buy toilet bowl cleaner, just like a toilet apply and let soak may take two applications but the stains will be gone.
sno-bowl cleaner used to be the go-to.

however I have been buying oxalic acid in powder form to mix up for rust removal for the past 15 years.

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redneck joe

Supreme Mariner
Joined
Mar 18, 2009
Messages
16,065
Oxalic Acid is made from Rhubarb.

its a naturally occurring acid, just like oranges and tomatoes
rhubarb? Cool...

but as a child of the 70's remember acid rain? Too much of something natural isn't always good and yes i know acid rain was not 'natural'. My pee is natural but too much kills plants. Ask my outdoor pee bush by my shed and it will agree with me...
 

bakerjw

Petty Officer 1st Class
Joined
Apr 3, 2013
Messages
370
It also comes from shamrocks and plants in the genus Oxalis. Ever eat a shamrock? Sour. That is the acid.
 
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