Had a lot of grout that wouldn't wash off newly laid tiles. Tried scrubbing and failed. Then tried this product. Worked perfectly to remove all residue. Easy to use, just followed the instructions.

I have gone through so many containers of this product, I tried EVERYTHING on my floor grout to no avail, this stuff is amazing, can not recommend enough. Pop a little on, scrub with a toothbrush, it's a little tedious cleaning up afterwards as product has a sticky residue, worth it though

Bought this to clean grout off newly laid tiles but then started using anywhere/everywhere there was a mark. Woks beautifully on cleaning the concrete driveway - even removed some hardwood stains. Cleaned patio tiles beautifully - removing spatters of tile adhesive and grout. It's easy to use by mixing a small quantity in water and applying with a broom or brush.
Works very well. removes so many marks and stains on outdoor surfaces
Can damage skin and eyes so must be used with extreme care. Wear protective gloves and goggles.