Applying grout to wall tiles creates a uniform look to the surface, helps bond the tiles together and protects the tiles from moisture. Grout application is a messy job so it is not uncommon for excess grout to get onto the face of the tiles. It is easiest to remove excess grout from wall tiles while the grout is still wet; however, you can remove even hardened grout from wall tile.
Fill an empty spray bottle with water. Lightly mist the hardened grout with the water. Fill a bucket with plain water.
Scrape the hardened grout from the tile using wooden sticks. Apply pressure and move the sticks back and forth over the hardened grout. Purchase wooden sticks from most home improvement stores or craft them yourself. Make sure the sticks are about 3/8-inch thick and an inch wide. Add more water, if necessary, and continue scraping until all of the hardened grout is off the tiles.
Dip a rag into the bucket of water and wring it out. Wipe down the face of the tiles with the rag. Go over the tiles with a dry rag to remove any haze or residue.
Lay paper towels soaked in sugar water over the hardened grout that was not removed with the sticks. Fill a bucket with 1 gallon warm water. Add 1 cup of sugar to the water.
Soak paper towels in the sugar water, and lay them over the dried grout. Allow them to remain on the tiles for a minimum of two hours before scrubbing the tile with a wet, nylon scrubbing pad. Rinse the tiles with a rag and plain water and dry with a clean rag.
Hold a grout float at a 45-degree angle. Run the float diagonally across the tile back and forth several times until the tile joints are packed full with the grout. Scoop up any excess from the tiles with the grout float.
Fill a bucket with warm water. Dip a large sponge into the bucket, and wring it out well.
Run the damp sponge diagonally over the face of the tiles, applying only light pressure. Go back and forth over the tiles several times. Rinse out the sponge frequently, and change the bucket of water as it becomes cloudy.
Go over the face of the wall tile with a dry rag to remove any residue. Wash the tiles again with the sponge and water if grout still remains on the tile. Always go over the tiles with a dry rag after using the water.