“Have suffered with black spots on patio for a few years even after pressure washing didn’t budge it! This stuff is amazing, left on overnight, did it late in evening when everyone including dog inside for night. Very powerful smell so wear a mask! Rinsed off next day and amazing results!”
“This stuff is the bomb! Our patio is light Cotswold Stone slabs and they had become so dirty we couldńt get them clean with the power washer. Went online and found HSD bought this product and applied as instructed almost immediately the black came out of the stone and once it was power washed it was like new again. Some areas need a second treatment.”
