When cleaning grout, avoid using bleach and other harsh chemical cleaners that might break down sealants. The best way to clean grout is using a natural grout cleaner.
We recommend mixing 1/2 cup of baking soda, 1/4 cup of hydrogen peroxide, 1 tsp dish soap. Mix together the baking soda, hydrogen peroxide and dish soap. Spoon mixture onto grout, wait 10 minutes, scrub and rinse.