For a satin surface, on a polyurethane finish, use pumice in 2F and 4F grades. To achieve a semigloss surface, use rottenstone (powdered limestone). Use one or the other, not both, or the coarser pumice will leave coarser scratches than the 2,000-grit abrasives.Pour mineral oil or paraffin oil onto the surface, and sprinkle it with pumice or rottenstone to form a slurry, as shown.