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.