Red Georgia clay has washed down on this concrete pad for about 7 years now and the home owner wants it cleaned off as best as possible. Ive tried a bleach solution and muratic acid. They didnt really work too well. I tried spots on the concrete and you could kinda tell a difference in the shade of the concrete but as far as cleaning it up nice, nothing. The whole thing has black and green mold junk on it. The green came off nice, about half the blackish looking stuff came off, and really none of the mud. It stays shaded all day if that matters any. any tips or suggestions?