Use warm water and wipe it over the surface of the tiles with a sponge. Then using some fine wire wool, rub gently over the grout which will begin to dissolve and rub off at the same time. Once the tile is clean and has no more hardened grout, wipe over with a damp cloth and leave to dry..
Related posts to how to remove grout from tiles surface
Work at the grout with light to medium pressure until you've removed all heavy deposits of grout, and then rinse off the tile with clean water. 4 Wet the grout that remains with clean water, and scour the surface of the tile with a damp nylon scouring pad..
Remove dried grout from ceramic tile using a hardwood implement, water and a plastic scrubbing pad. Once grout cures, it becomes much more difficult to remove, but most grouts are removable with Remove dried grout from ceramic tile using a hardwood implement, water and a plastic scrubbing pad..
I was applying grout to ceramic subway tile, and ended up having to leave the job before I could sponge clean the excess grout.
If you are grouting ceramic or porcelain wall or floor tiles, it can be easy to leave small lumps of grout on the tiles surface and around the joints..