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RE: Rust stain remover


Another off the shelf product containing oxalic acid is Zuds. It comes in a liquid slurry or a powder much like a cleanser product. It also has abrasives like cleansers so it may scratch some surfaces.  I use around the house occasionally for removing light rust stains from wood, some fabrics, concrete, and countertops.  I am a little “rusty” on my chemistry, but I believe oxalic works as  a reducing agent that a takes the ferric iron (rust) to soluble ferrous state. It may also have chelating properties like citrates, but I am a not sure of that.  Like most everything else in substitution assessments, it has some risks.  I found this definition via Google: A dicarboxylic acid, chemically COOH—COOH. Poisonous in large amounts; present especially in spinach, chocolate, rhubarb, and nuts. The toxicity of rhubarb leaves is due to their high content of oxalic acid.  High concentrations of oxalates in the urine can form kidney stones; while most of these oxalates are of endogenous metabolic origin, patients with hyperoxaluria are advised to avoid dietary sources of oxalates.

So if you use oxalic acid products around Thanksgiving, you may want to go light on the rhubarb pie – at least a second helping.

John Sparks





From: owner-p2tech@great-lakes.net [mailto:owner-p2tech@great-lakes.net] On Behalf Of Callahan, Mike
Sent: Wednesday, November 19, 2008 2:06 PM
To: Lockwood, Paul; p2tech@great-lakes.net
Subject: RE: Rust stain remover




The most common way to remove rust stains is with an acid.  Hydrofluoric acid is most effective but very dangerous to handle. Commercial rust removers most often contain oxalic acid.  Bar Keepers Friend is a scouring powder with oxalic acid. Being an organic acid, oxalic acid is biodegradable and acceptable for sewer discharge. The abrasive solids might be an issue, but only if you were trying to use them on an industrial scale. Small use on an occassional rust stain should not be an issue.  I don't know if any commercial products use citric acid, but it too should be capable of removing light rust stains. Once the stain is removed, you want to flush the surface with lots of water (to remove the acid) and if metal, apply a protective oil-based coating. Acid cleaned metal will quickly rust again if you don't take measures to protect it from air and moisture.  Hope this helps.



-----Original Message-----
From: owner-p2tech@great-lakes.net on behalf of Lockwood, Paul
Sent: Wed 11/19/2008 5:09 AM
To: p2tech@great-lakes.net
Subject: Rust stain remover

Our Administrative Services building maintenance department switched to green cleaning products for all State buildings with one exception; rust stain remover.  They asked us for an environmentally-friendly product that will remove rust stains from a variety of surfaces such as concrete, metal, porcelain, etc.


I’ve been to P2Rx, TURI, Green Seal, green shopping sites, etc., and found dozens of products that profess to remove rust stains but I’d prefer to recommend a few I know to be effective.  Someone here personally recommended “Bar Keepers Friend,” but I have no idea how environmentally benign it is.


Does anyone know of a product we can recommend?




Paul Lockwood

NH Department of Environmental Services

P.O. Box 95

Concord, NH 03302-0095

(603) 271-2956



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