SH doesn't remove brown. I'd try a degreaser or diluted aluminum brightener. Acid removes dirt staining.
Mike, besides potentially lowering the pH of a water body what are the risks to the environment?Diluted muriatic acid works very well at brightening concrete. I used it for spot cleaning my driveway a couple of years ago when I moved into my house. It's bad for the environment, so I wouldn't suggest using it for large areas unless you can capture the runoff and dispose of it safely.
I was thinking that too, it kinda looks like my driveway that I water based stained. I use HD-6600MMA on top of it (it's slick when wet) but you don't have to worry about some vehicle dropping oil all over it.Just stain the driveway a light gray maybe? Would probably make it virtually disappear.
