I recently moved into a rental that has ceramic tiles in all rooms but one. The living room alone is 20′X22′ and the grout was black. Not supposed to be, but it was. I washed the floors with Spic and Span, used Bar Keepers Friend cleanser and a toothbrush and the grout was still horrible. My daughter suggested MelaMagic. Just 1 tablespoon in a gallon of water is all it took. Poured a bit onto the tiles, let it set for a bit then scrubbed with a brush. WOW! the grout is white! It’s still going to take a bit to get through the whole place – 2 bedrooms, 2 baths, kitchen and living room – but with far less scrubbing and time involved. Just one more product I’ve fallen in love with. Thanks Melaleuca!