Ceramic tile just installed. Installer did not clean the grout as he laid the tiles. Two or three days passed and now the off-white grout will not come up off the sandtone colored tiles. He has tried "TileLab"grout and tile cleaner, sponge mopping, mopping, and mopping. Nothing has removed the white botches from my tiles. Is the job ruined. What is out there that will loosen the grout that has dried on my tiles. HELP!!!