We cleaned and conditioned some ceramic tiled lobbies in an apartment complex last year and they came out very well. The tiles (2 " tiles) are matte finished and the owners want to see what we might do to put a little gloss on the surface. I told them that any kind of topical such as polymer would be a very bad idea. The grout lines are deep and the stuff will only gum everything up. I am going to test a ceramic polish on the tiles next week, but don't have a lot of high hopes for more than a little gloss (maybe a little is ok). In any event, perhaps there is some sort of conditioning agent that can be applied periodically or an impregnating sealer with some gloss qualities that I can use to brighten it all up.