Try using a professional grout cleaner designed for epoxy grout haze.
Ceramic tile haze remover.
You can use a commercial acidic grout haze cleaning compound.
Hardened grout haze on ceramic or porcelain tiles will require an acidic cleaner and a scrubbing pad to remove the grout haze.
Avoid using a green tile sponge as it may transfer color to the grout.
Heavy duty acidic cleaner is a fast acting heavy duty acid cleaner for textured non polished natural and manufactured surfaces.
You can also make a homemade grout haze cleaner using household vinegar.
Be careful not to confuse grout sealer or grout cleaner with grout haze remover.
A couple of well known brands are dupont and sci.
Grout haze remover is widely available at any tile store home improvement store or hardware store or online.
Before you start removing grout haze allow grout to harden fully.
Epoxy grout haze can be difficult to remove with mild cleaners or scrubbing tools.
Use a mop or spray bottle to apply the cleaner to the flooring then scrub each tile with a white tile sponge.
Removing the grout haze off of stone tiles will require using a non acidic grout haze remover product.
Diluted vinegar on porcelain or ceramic tile only and a nylon scrub pad and a commercial grout haze remover.
Heavy duty acidic cleaner.
Mix 1 part vinegar to 4 parts water and use this to wipe down the tiles.