If you are faced with dirty grout, a good scrubbing with a scrub brush and a general purpose cleaner is often the best solution. Once you have finished scrubbing, be sure to thoroughly rinse the grout to remove any loosened dirt. We suggest you use the scrub brush along with plenty of fresh water to result in the cleanest surface possible. Let this dry overnight. Now apply a good sealer before the grout gets dirty again. It may be easier to remove and replace extremely dirty grout than it is to clean it, so consider this as an option.