Grout that is missing, cracked or discolored can make tiles on countertops or backsplashes appear old and dingy. Missing grout between tiles can also cause water damage to the substrate of a countertop. Replacing tile grout can be an inexpensive and simple do-it-yourself project if you have the right tools and materials. Even if large amounts of tile grout need to be replaced, you can easily repair grungy-looking tiles.
Use a sponge to apply the vinegar and water solution to the area of tile grout that needs repairing. This will clean mildew from tiles and grout. Use the grout saw on the grout lines between tiles to remove cracked or discolored grout. Wear safety glasses while using the grout saw.