I had Groutmasters clean my 17 year old ceramic tile in the hallway, kitchen and my masterbath. My grout and tile were quite dirty and dark. 3 months later, I have to say it's the best money I spent all year long on my home. I walk around my main floor and love my clean grout and tile. They were professional and very clean. I also love the special tile cleaner that was recommended and will order that again.
Thanks so much again and sorry for taking so long to review.