Concrete grout is used between tiles to join each other. If it is not properly sealed when the tile is installed, grout can easily absorb the liquid and stain because it is very porous. The ideal is to clean the grout as soon as possible and seal it to avoid further problems. A pressure cleaning machine can be used to clean the tile.
Instructions
1 Mix oxygen bleach with water. Use several balls for a gallon bucket of water. Stir until dust dissolves.
2 Mop or sponge on the floor and let stand for half an hour. If the grout absorbs water, mop in more solution to make it moist all the time.
3 Rub the floor surface, concentrating on the tile, with a power washer with a hard-bristle attachment. Add more solution while rubbing.
4 Rinse with clean water and towel dry to remove excess water.