Charlie Bress wrote:
I was working on the car and noticed a lot of built up corrosion around the
battery terminals. No big deal, right?
I cleaned of the terminals with a wire brush, replaced the bolts and nuts
(this is a top mounted terminal battery) and then I took the hose and
rinsed of the top of the battery.

Now comes the problem. Wherever the run of went there are nice ugly brown
stains. The driveway is poured concrete and my understanding is that it is
"fiber" reinforced.

What is the best way to clean these marks off? Looking at Google for
concrete cleaning I see muriatic (hydrochloric) acid or phosphoric acid.
These tend to be nasty to work with. Is there something else that will work?
The stains look like rust, but C-L-R doesn't seem to touch it. I tried some
full strength. It might have worked a little.

I am not sure it is rust. I don't know what has been put in the concrete.
The driveway does not show rust marks where it is exposed to the weather.


Charlie


I've tried rust stain removers, with no results.

........it may sound silly, and it would not likely be appropriate for a
large area....I painted concrete in our condo atrium after a neighbor
left some dark brown blotches from staining wood furniture. Cheap, easy
if you can mix paint colors with some skill. Acrylic craft paint from
local hobby store. Our concrete was old and stained anyway, and it
takes some experimenting to get the colors right. I used very little on
a flat-end stencil brush, put on two colors. First color was for the
base, or shadow, part of concrete texture - gray with a little blue and
brown. Then, the lighter part of the texture (top of gritty particles)
use gray with a bit of yellow or gold. Have to mess with it to get it
right, and it washes off easily if not dry. Can't have the brush
loaded, as you don't want the concrete to look painted, and you need to
feather it to blend with rest of concrete. Has lasted a couple of years
so far in our sheltered atrium - open but with roof over it.