How to Repair Grout: 9 Steps (with Pictures) - wikiHow
· 1. Clean the damaged grout with white vinegar and water. That way you can see the exact color of the grout and buy new grout that matches it. Mix one part white vinegar and one part water in a bowl or bucket. Then, dip a clean toothbrush in the mixture and scrub the damaged grout until all the dirt and grime comes off.