Protect your hands with rubber gloves and dip your cheesecloth or terry cloth in water.
Cleaning grout residue from slate tile.
Use another clean sponge to rinse the scrubbed slate tiles with.
Since nothing you tried removed the grout haze i d guess that the slate probably wasn t properly sealed before the grout was applied.
Instructions wait for the grout to cure wait at least 10 days for newly installed grout to cure before using grout haze remover.
Remove grout haze with water and cheesecloth.
Clean the floor sweep or vacuum the floor thoroughly then wet mop the tile to dampen it.
Wring thoroughly as too much water can damage.
Mix the grout haze remover put on nitrile chemical resistant gloves.
Normally a scotch brite pad water and a little rubbing will remove grout residue and the hazy appearance it causes.
How to remove grout haze from a slate floor 1.