It is clay tile that was sealed with and sealer that is worn in many places. Scratch test exposes bare clay. I don't think that cleaning and resealing is proper way to restore it. I recommended stripping, grout color sealing and topical sealer to finish. We have done many stripping jobs (including Saltillo) and we are expirienced in it but we have not worked on bare clay terracotta tile.

I am concern about stripping this tile because of stripper absobsion into the tile. How do you guys do it? Do you use special stripper that is safe for this type of tile? How big sections do you do at one time, etc? Any help is greatly appreciated.