How to Remove Oil & Rust Stains From Concrete
Concrete is a highly porous substance and, therefore, a very absorbent surface. Driveways and garage floors are often made of concrete, and work done on cars or other machinery can leave tricky rust and oil stains. Fortunately, with a little time and patience, and depending on the severity, the size of the stain and how long since the substance touched the concrete, it is possible to remove it on your own.The Army Corps of Engineers recommends various ways to remove rust and oil stains. Does this Spark an idea?
Things You'll Need
- Bucket
- Oxalic acid
- Water
- Sodium citrate (citric acid)
- Glycerol
- Diatomaceous earth or talc
- Trowel
- Flannel rag
- Pane of glass or thin concrete slab
- Microbial cleaner
Instructions
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Rust
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1
For light stains, mix 1 pound of oxalic acid per gallon of water, apply it to stained area, and wait 2 to 3 hours. Go to step 2. If it is a deep stain, go to step 3.
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2
Scrub the surface with stiff brushes while rinsing with clear water.
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3
For deep stains, make a poultice of 11 ounces sodium citrate, 2 quarts lukewarm water, and 2 quarts 12 ounces of glycerol mixed with diatomaceous earth (which looks and feels like talcum powder) or talc.
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4
Apply this mixture to the stain with a trowel, and leave it for 2 to 3 days.
The poultice should absorb the rust, and you can wipe up the waste material. Dispose of it properly.
Oil
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5
If an oil stain is freshly spilled, wipe it up with an absorbent paper (shop rags are great for this). If the stain is old, go to step 2.
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6
Cover the stain with a piece of flannel soaked in acetate.
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7
Cover the flannel with a pane of glass or thin slab of concrete for 10 to 15 minutes.
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8
Rinse.
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1
Tips & Warnings
Chris Sullivan also recommends applying a poultice, but for larger, more serious stains, he suggests using products composed of single-cell microorganisms that eat the oil. "Enzymes and oxygen digest the oil and turn it into carbon dioxide and more microorganisms. When the food source (oil) is gone, the microorganisms die, leaving the concrete clean and oil-free."
Handle all toxic and hazardous materials carefully and according to manufacturer's directions. Do not store leftovers; dispose of them according to state/city regulations for hazardous materials.
