The former owner of my house installed Mexican tiles in the Master BR and Bath. They were treated with a process that she referred to as "pickling" which covered the tiles with a pale pinkish-beige coating. In places where I have spilled water, some of the coating has come off, revealing the original terra cotta color. I would like to restore the tiles to their original color. Several questions: How can the coating be removed? Will it all come off? Assuming removal is possible/feasible, how should the tiles then be treated? Thanks for any help you can give me.