Review on Grout-Eez Ultimate Grout Cleaner: Effortless, Powerful, and Safe for All Grout Types. by David Ross

This cleaner had no effect on our solution. I leave the Fugen-Eez on for 15 minutes and dip the grout cleaning brush directly into the liquid cleaner before brushing. Unfortunately the stains were not removed. Sorry, floor people, but Grout-eez didn't clean our grout. Updated 9/25/17: The Floor Guys helped me a lot with my situation. They supported their product, helped solve my problem and when their suggestions didn't work, they immediately refunded the money for the purchase. So I'm increasing my rating by one star as they were very helpful after the sale. It might solve your grout problem, if not, it was a pleasure working with Floor Guys.