I am looking for solutions before I replace this one ceramic tile. I was removing dry grout and dry paint from the ceramic tiles with a non metallic bit using my electrical drill at low RPMs. It looks that the contact was to close and it buffed/stained the ceramic tile in the spots. I noticed it after I cleaned the entire area. When they are wet, or sealed with a wet sealer, usually imperfections could be hidden. In this case, after a damp mop, you can still see the areas stained. What can I do before I pull the chisel out? Any tips? At this point I want to try anything before I remove the ceramic tile. Thanks in advance.