Grout must set for 15 to 30 minutes before it is wiped for the first time and another 3 hours before it is wiped a second time, according to BobVila.com. In both stages, the grout should be wiped with a wet sponge to remove excess grout on the tile.Know More
The grout must be allowed to dry for several hours or overnight after the wet wipe. Once the grout is dry, a haze forms on the tile. The haze should be rubbed loose with a dry towel, and then the remaining dust must be swept off. Using a wet towel for the last step often causes the haze to form again.