How do i get this out?

[gman546]

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?

 

[flashback]

Wet sand it with 800- 1000 grit sandpaper and then buff with a good buffing compound.

 

[Scott Danforth]

get some oxalic acid (wood bleach) and mix it up

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

 

[tpenfield]

I keep a bag of oxalic acid on the shelf for cleaning mineral and iron stains.