Work on three or four.
Cleaning grout residue from slate tile.
Wring thoroughly as too much water can damage.
Mix the grout haze remover put on nitrile chemical resistant gloves.
Use another clean sponge to rinse the scrubbed slate tiles with.
Remove grout haze with water and cheesecloth.
Clean the floor sweep or vacuum the floor thoroughly then wet mop the tile to dampen it.
Instructions wait for the grout to cure wait at least 10 days for newly installed grout to cure before using grout haze remover.
Since nothing you tried removed the grout haze i d guess that the slate probably wasn t properly sealed before the grout was applied.
Scrub the surface of the slate tile with a generous amount of water and a nylon scrub sponge.
Pick up the dirty water with a clean grout sponge.