Hey guys, can someone help on how to clean this brick, looks like e-flo but I tried cleaning with an acid cleaner specific for e-flo, didn't work. The picture is before I tried the acid but the after picture didn't come out. The acid cleaner didn't work, even at its full strenght. The owner said its from the water sprinklers???? Tried to upload pictures but it said file was too big, What do I do about picture uploading?