Cleaning a stained concrete driveway

[Charlie Bress]

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

[Rein]

the acid solutions are really the best and cheapest ways to fix it. Mix it with water, apply and the rust comes out, gauranteed. Just wear safety glasses. I had a landscaping company drop ironite on my concrete and had tons of rust specs all over it. I complained to them. They asked if I had some pool acid left over and if they could use it. They removed it in no-time.

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[Norminn]

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.

[Norminn]

clipped

Only trouble with acid is that it removes the concrete.

[willshak]

Since battery acid is suphuric acid, putting another acid (muriatic acid aka hydrochloric acid) on the stain doesn't seem to me to be the answer. You might try a solution of baking soda and water on the stain. Let it sit overnight before washing off.

[willshak]

I said 'a solution', but it would be more of a paste.

[Phisherman]

[mark]

Not sure what CLR is, but is it oxalic acid? That's what Rust Out is.

[Rein]

Not here. My guess is they mixed it with enough water to prevent that. Remove NO-SPAM from email address when replying

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