paint

well i am going to try a small area tomorro and see what happens.... but another question... how do i know that i have taken out the 600 grit sanding marks with the 1000 grit and the 1000 with the 1500 and so on...
i tried a small spot and i dont see much much difference in the marks other then it getting a little brighter as in going from darker to lighter scratch marks.. any tips on telling the difference