Bests & Worsts Reviews from Amazon

OK, brought this stuff, 2 large bottles at Costco. Figured if it was crap as I expected it would be, I'd take it back since that's how Costco works. Watered it down as instructed and sprayed one side of two stone steps which were covered in black Mildew. About a week later I noticed a definite difference but wasn't blown away by the results. It does say though, give it a few weeks. Yeah, right. However, I am about a month into leaving it and it's amazing. One side is still the black mildew and the other is about 80% cleaner and brighter. I am going to give another little spray and I reckon in 2-3 more weeks, it'll be as new. I deliberately didn't scrub it either! So, I live in Norcross, GA. By the river and lots of mildew so this is going to be awesome but I want to know why I haven't heard much about this stuff. How the heck does it work? It says it works with the wind and rain to slowly remove ingrained stains and keep stuff clean. It does exactly what it says it does and that for me, is a miracle in itself. I have also, for fun, sprayed some shapes into my black mildew driveway and I can already see it working, I just want to know HOW :)