MARBLELIFE Maxout Tile and Grout cleaner!! It is a miracle in a bottle. We have been in our house 15 years and just used it to clean the grey grout in our kitchen floor. I had tried other products without much success. Honestly, it removed 99% of the stains in the grout. I think I found 2 small spots that won't come up. But all the food and dripped coffee stains are gone. It looks like new - really!
One tip: I went to Sally's beauty supply and bought a squeese bottle with a slanted tip and small hole in tip. It made the application so easy. You could just walk along the grout and apply as you walked. Using the main bottle, it came out way too fast.
My husband is not as excited about the sealant. Moisture still seeps in (especially where our dogs drink from the dish).
We ordered the products from Johnnie Chuoke's Home & Hardware | Just another WordPress site
(he recommended it in our local paper) or you can go to marblelife.com.