Create a mixture of 1 tablespoon liquid dish soap, 3/4 cup chlorine bleach and 1 gallon warm water. Stir the ingredients until they are well-incorporated.
Slip on a pair of rubber gloves and work the bleach mixture into the grout with an unwanted toothbrush. The chlorine bleach removes any dirt, soap scum and grime on the grout.
Rinse the grout with cool water and apply a grout haze cleaner that contains sulfamic acid according to the package directions. Allow the commercial grout haze cleaner to remain according to directions.
Rinse away the cleaner with cool water.
Dry the grout with a soft cloth to prevent future haze.