Do not use on marble and limestone surfaces, including travertine.
For more stubborn stains, reapply and scrub with a soft bristle brush as necessary.
For light to moderate grout stains, allow the cleaner to sit for a couple minutes and very little scrubbing will be required. For deeper, darker or older stains allow the cleaner to soak longer and expect to do a good bit of scrubbing.
Breaks down the toughest grout stains caused by mold, mildew, soap scum and hard water
Dirt buildup, mold stains, mildew stains, soap scum and hard water stains