We bought a house that had saltillo tiles that appeared to have a dark brown stain on it, then sealed with something.Several companies came in to help us identify what was on it, without any luck. We used numerous strippers without any luck getting off whatever sealer the previous owners used. As a last ditch effort I used a polyurethane wood stripper, which took off the sealer. Will this stripper harm the tile or grout? My question. Is there a stripper on the market which can remove 500 sq ft of this polyurethane sealer or should we just get rid of the tile? It appears in good shape underneath.I've tried everything 4 companies recommended and put in alot of work, but I give up. Please help.