Grout, which is installed between tiles, is made out of cement and sand. If you do not regularly clean your grout, it will collect dirt and mildew. Dirty grout becomes discolored and can be an eyesore. Grout can usually be cleaned with household products and elbow grease. There are a number of different ways you can clean dark grout.
Combine 2 cups of water, 10 drops of liquid dish detergent, and 1 cup of baking soda. Pour the solution into a spray bottle.
Spray the solution onto the dirty grout. Let the solution sit on the surface for 5-10 minutes.
Scrub the dark grout with a soft cloth or a sponge.
If dirt or grime remains, try solutions of 2 cups water and 1 cup distilled white vinegar, 2 cups water and 1/2 cup nonsudsing ammonia, or 2 cups water and 1/2 cup chlorinated bleach.
Apply a steam cleaner to the grout for about 15 seconds. Scrub the dirt away with a toothbrush.
Rinse the newly cleaned grout with water. Dry the area thoroughly.