# How Do I Remove Rust Stains From A Concrete Driveway? **URL:** \ **Category:** Factual Questions\ **Created:** [September 23, 2004, 3:51pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691 "2004-09-23T15:51:27Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![JimMacMillan](https://avatars.discourse-cdn.com/v4/letter/j/7bcc69/32.png) [@JimMacMillan](https://boards.straightdope.com/u/JimMacMillan)\ **Post date:** [September 23, 2004, 3:51pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/1 "2004-09-23T15:51:27Z")
Actually I am asking for my neighbor. He had a radiator leak and the driveway now has some ugly rust stains. Ideas? TIA Jim P.S. I did a search of SMDB for “Concrete & Rust” and found nothing conclusive. ---
**Author:** ![Phlosphr](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Phlosphr](https://boards.straightdope.com/u/Phlosphr)\ **Post date:** [September 23, 2004, 3:56pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/2 "2004-09-23T15:56:45Z")
Hmmm, concrete is notoriously porous and when rust hitches a ride on some water, it can do some ugly things when it soaks in. I;d recommend a bleach solution, and a high powered hose. Or even a powerwasher. I know the stains are not permenant, as I grew up with a concrete driveway, and this happened from time to time. Maybe even the same reason the OP mentioned at one time or another. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [September 23, 2004, 3:57pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/3 "2004-09-23T15:57:38Z")
I have some kitchen cleaner that removes rust stains and the active ingredient is oxalic acid. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [September 23, 2004, 5:05pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/4 "2004-09-23T17:05:22Z")
I once lived next door to a man who had a big rust stain in his driveway. One day, though, he had a wrecker haul it away. ---
**Author:** ![Mr.Duality](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.duality/32/4098_2.png) [@Mr.Duality](https://boards.straightdope.com/u/Mr.Duality)\ **Post date:** [September 23, 2004, 5:29pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/5 "2004-09-23T17:29:03Z")
[http://www.ehow.com/ehow/ehowDetails.jsp?index=1055&id=18444](http://www.ehow.com/ehow/ehowDetails.jsp?index=1055&id=18444) ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [September 23, 2004, 5:30pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/6 "2004-09-23T17:30:36Z")
Citric acid, tartaric acid, oxalic acid – these are all effective at removing rust stains. Oxalic acid is commonly used, and is available in cleaners such as ZUD, and is also sold as “wood bleach.” Chlorine bleach and a powerwasher sound like a good way to clean mildew stains, maybe tire marks, but not much else. ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [September 23, 2004, 6:54pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/7 "2004-09-23T18:54:07Z")
ACE Hardware recommends [Jasco® Concrete Clean & Lighten](http://www.acehardware.com/product/index.jsp?productId=1340360). ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [September 23, 2004, 7:00pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/8 "2004-09-23T19:00:25Z")
I just meticulously powerwashed my entire driveway and sidewalk. It removed everything **BUT** the rust stains. For the record, those rust stains were produced by Ironite fertilizer if it matters, but I’m thinking rust is rust regardless of the source, ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [September 23, 2004, 7:07pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/9 "2004-09-23T19:07:50Z")
I’ve had good results with Muriatic acid. You should be able to find it at pool supply houses and any company which sells brick, block, and masonry supplies to the trade. ---
**Author:** ![The\_Flying\_Dutchman](https://avatars.discourse-cdn.com/v4/letter/t/9fc348/32.png) [@The\_Flying\_Dutchman](https://boards.straightdope.com/u/The_Flying_Dutchman)\ **Post date:** [September 23, 2004, 7:09pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/10 "2004-09-23T19:09:03Z")
Nothing works as good as Muriatic acid. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [September 23, 2004, 7:21pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/11 "2004-09-23T19:21:15Z")
> [@grienspace](#): > > Nothing works as good as Muriatic acid. Well, 37% Hydrochloric acid is just as good. 😉 ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [September 23, 2004, 7:33pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/12 "2004-09-23T19:33:51Z")
From an Ask The Builder site… note runoff warning. > [@](#): > > You need to buy some oxalic acid to remove the rust stains. It is a crystalline toxic organic compound that is mixed with water. Commercial laundries often use it to remove rust stains from fabrics and it will really work well as it chemically reacts with the iron oxide in the concrete. The iron oxide is put into solution with the acid and then simply rinses away. Be careful using this acid and follow all instructions on the product label. It is a good idea to capture the runoff from the process as otherwise it may kill nearby plants and trees. ---
**Author:** ![asterion](https://avatars.discourse-cdn.com/v4/letter/a/4da419/32.png) [@asterion](https://boards.straightdope.com/u/asterion)\ **Post date:** [September 23, 2004, 7:40pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/13 "2004-09-23T19:40:30Z")
> [@grienspace](#): > > Nothing works as good as Muriatic acid. I can’t believe I just used SciFinder Scholar to look that up. But I have got to use that in lab sometime. Maybe relabel the bottle if people keep walking off with it (like I’ve had in the past.) ---
**Author:** ![olefin](https://avatars.discourse-cdn.com/v4/letter/o/d78d45/32.png) [@olefin](https://boards.straightdope.com/u/olefin)\ **Post date:** [September 23, 2004, 10:01pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/14 "2004-09-23T22:01:08Z")
> [@Squink](#): > > Well, 37% Hydrochloric acid is just as good. 😉 I thought it was 31.45% Hydrochloric acid would be just as good. 😉 ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [September 23, 2004, 10:30pm UTC](https://boards.straightdope.com/t/how-do-i-remove-rust-stains-from-a-concrete-driveway/265691/15 "2004-09-23T22:30:14Z")
> [@olefin](#): > > I thought it was 31.45% Hydrochloric acid would be just as good. 😉 What’s that figure in Baume? 😉