removing tile grout

anyone had any luck removing tile grout that was left on too long....we had a guy come in and install tile behind the countertop in our laundry room, about a 2 ft high backsplash....we picked out non glazed tile to match the kitchen backsplash...anyway, he installed the tile, came back the next day and used the white thinset stuff (we still have the bag that he left).....anyway, now we cant get him to come back...it's been 3 weeks now...we have tried everything to remove the glaze left on the tiles...nothing seems to work....we wipe it off real good, and 30 minutes later, it shows up again...we have used commericial cleaners from the home depot, we even used some white vinegar someone had recommended...nothing seems to work!...any ideas?

was thinking about maybe buffing it to see if that will work, as i cant really sand it without scratching the tile / removing the finish! [img]/forums/images/icons/confused.gif[/img] [img]/forums/images/icons/confused.gif[/img]

You can try sulfamic or muriatic acid. Start with a fairly dilute solution and go to a more concentrated solution if necessary. Also, check it first on a scrap piece of tile to make sure it doesn't affect your tile. This should work with a conventional thinset grout. If its an epoxy grout I'm not sure if it will work.

The muriatic acid is worth a shot. Just be very careful. It will eat your pants, shirt, hands, and anything else it touches, and the fumes will take a shiny piece of metal and leave it a rusty wreck.

Steve

i purchased this stuff from a tile center today...called aqua-mix phosphulric acid.....it looks pretty good now...i'll see how it worked in the morning...the tile always looks clean when it is wet, but the haze reappears a few hrs later....i also got a drywall sanding block, which the tile center guy said to use before the acid.....that helped quite a bit and didnt scratch the tile at all.....the black blocks that sheetrock guys use.