Cleaning a stained concrete driveway

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 22 Oct 2004 12:24:20 -0400, "Charlie Bress"

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.
Remove NO-SPAM from email address when replying
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
clipped

Only trouble with acid is that it removes the concrete.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Not here. My guess is they mixed it with enough water to prevent that. Remove NO-SPAM from email address when replying
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Charlie Bress wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Charlie Bress wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
willshak wrote:

I said 'a solution', but it would be more of a paste.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hydrochloric acid is very strong and could easily damage concrete. I suggest using a power washer. If you want to try some cleaners, I suggest "Zud" or "BarKeeper's Friend."
On Fri, 22 Oct 2004 12:24:20 -0400, "Charlie Bress"

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Not sure what CLR is, but is it oxalic acid? That's what Rust Out is.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Oxalic Acid is ingredient in BarKeepers. Also packaged as one of the wood bleaches found in paint stores.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.