How do you remove oil stains from concrete?
Fresh oil comes off with absorbent material and dishwashing liquid. Old oil needs something that pulls it back out of the concrete, which usually means a degreaser or a poultice. Start with the gentlest option and only escalate if it does not work.
The reason timing matters so much is that concrete is porous. Oil does not just sit on top, it soaks in. In a Perth summer a slab sitting at 50 degrees in the afternoon sun will draw a spill in far faster than the same slab in July.
| Stain | Best method | Notes |
|---|---|---|
| Still wet | Absorbent material | Cat litter or baking soda. Do not hose it |
| Fresh, small | Dishwashing liquid | Grease-cutting type, nylon brush, warm water |
| Light residue | Baking soda paste | Good on plain unsealed concrete |
| Stubborn, automotive | Concrete degreaser | Check it suits your finish first |
| Old, soaked in | Poultice | Draws oil out as it dries. May need repeating |
| Treated but marked | Pressure wash | Wide spray, low pressure, keep moving |
Before you start cleaning
Check what sort of concrete you are dealing with first. A method that is fine on a plain slab can strip the sealer off an exposed aggregate surface, and strong chemicals can shift the colour of coloured concrete or dull a honed or polished finish.
If you are not sure whether your concrete is sealed, put a few drops of water on a clean section. Water that beads up means there is sealer on it. Water that soaks straight in and darkens the concrete means the surface is unsealed or the sealer has worn out.
You will usually want:
- Gloves and safety glasses
- Paper towel, rags or an absorbent powder
- A stiff nylon brush
- A bucket of warm water
- Dishwashing liquid or a concrete cleaner
- A hose you can control the pressure on
Keep the area ventilated, and keep the dirty water out of stormwater drains, garden beds and pools. Follow whatever the product label tells you.
1. Absorb a fresh spill immediately
The single most useful thing you can do is soak up the oil before it gets into the concrete. Cover the spill with cat litter, baking soda, sawdust, cornflour or a commercial oil absorbent.
Leave it at least 30 minutes, and several hours for a big spill. Press it gently into the oil rather than rubbing it around, because rubbing just spreads the stain wider.
Sweep it into a bag and dispose of it according to your local council requirements. Repeat if the concrete still looks wet.
Do not hose a fresh spill. Water spreads oil across a much bigger area and carries it into the soil and drains, which turns a small problem into a large one.
2. Scrub the concrete with dishwashing liquid
Dishwashing liquid is built to cut grease, and for a fresh or light stain it is often all you need.
- Clear off any oil still sitting on the surface.
- Squeeze grease-cutting dishwashing liquid straight onto the stain.
- Leave it 10 to 15 minutes.
- Scrub with a stiff nylon brush.
- Add a little warm water and keep scrubbing.
- Rinse carefully.
- Let it dry fully before deciding whether it worked.
Concrete always looks darker wet, so wait until it is properly dry before you judge the result or go again.
Do not reach for a steel wire brush. Tiny fragments of the wire stay behind in the concrete and rust, so you trade an oil stain for a scatter of orange spots. Wire also scratches sealed, honed and polished surfaces.
3. Draw the oil out with baking soda
Baking soda absorbs surface oil and gives you just enough grit to lift a light stain without damaging anything.
Tip a generous layer over the stain and leave it at least 30 minutes, or several hours for a recent spill. Add a splash of water to make a paste, scrub gently with a nylon brush, rinse and let it dry.
It works best on:
- Small oil spots
- Recent spills
- Light residue left behind after a first clean
- Plain, unsealed concrete
It will not do much for an old stain that has soaked deep into the slab. If the mark is still there after one or two goes, move up to a proper degreaser instead of scrubbing the same spot over and over.
4. Apply a concrete degreaser
A concrete degreaser is made to break down engine oil, grease and the rest of it. For driveway stains, garage floors and workshop areas it is usually the right tool.
Pick one labelled for your type of concrete, and check whether it is safe on coloured, sealed or decorative surfaces before it goes anywhere near the slab.
- Sweep off loose dirt and surface oil.
- Apply the degreaser to the stain.
- Leave it for the time on the label.
- Scrub with a nylon brush.
- Rinse or collect the residue as directed.
- Let the concrete dry completely.
- Repeat if the product allows it.
Mixing it stronger than the label says does not work better. An over-concentrated cleaner can discolour concrete or wreck the coating on top of it.
5. Treat an old oil stain with a poultice
An old stain sits below the surface, which is why scrubbing only ever cleans the top of it. A poultice is an absorbent paste that pulls the oil back up out of the pores as it dries out.
You can buy commercial concrete poultice products, or follow the instructions that come with a compatible absorbent powder and concrete cleaner.
- Clean the loose dirt off the area.
- Mix the poultice as the product directs.
- Spread a thick layer over the whole stain.
- Cover it if the instructions say to.
- Let it dry out completely.
- Scrape or sweep the dried material away.
- Clean up whatever residue is left.
An old stain often needs more than one application, and even then a faint shadow can remain where the oil has discoloured the concrete itself.
Do not improvise a chemical mix of your own. Some combinations produce genuinely dangerous fumes, and others will damage the slab.
6. Pressure wash the concrete carefully
Pressure washing is good for clearing loosened oil and cleaning residue off durable outdoor concrete. It works best after a degreaser has already done the hard part, not instead of one.
Use a wide spray pattern, start on low pressure, keep the nozzle moving and hold a consistent distance. Parking high pressure on one spot leaves visible lines or takes the top layer off entirely.
Go especially carefully on:
- Exposed aggregate
- Coloured concrete
- Sealed driveways
- Concrete near expansion joints
- Older or cracked surfaces
- Pool surrounds
Too much pressure loosens aggregate, strips sealer and leaves you with a patchy finish. Worth reading up on the right way to clean exposed aggregate concrete before you start, since it is on a lot of Perth driveways and it is easy to damage.
Contain the oily runoff and keep it away from stormwater drains.
What should you avoid using on concrete?
Plenty of shortcuts leave the slab looking worse than the stain did. Avoid:
- Harsh acid cleaners, unless a professional has specified and applied them
- Steel wire brushes
- Undiluted chemicals
- Mixing cleaning products together
- Hosing fresh oil into a drain
- Excessive pressure washing
- Scrubbing the same spot aggressively over and over
- Sealing over a surface that is still contaminated
Solvents are a particular trap. They dissolve oil without necessarily removing it, so you can end up pushing the contamination deeper or spreading it into a larger mark than you started with.
Can oil stains be removed from sealed concrete?
Usually more easily, yes, because the sealer slows the oil down before it reaches the concrete. Blot the spill straight away and clean it with something approved for that coating.
Stay away from strong solvents and hard scrubbing. They soften, cloud or strip sealer, and once an area has gone dull or patchy it generally needs professional cleaning and resealing to look right again.
A good concrete sealer makes staining much less likely, but it does not make concrete stain-proof. Spills still need cleaning up promptly.
Can you completely remove an old oil stain?
Sometimes. Plenty of old stains fade a long way without ever disappearing entirely. What you get depends on:
- How long the oil has been sitting there
- How much was spilled
- Whether the concrete was sealed at the time
- How porous the surface is
- What has already been tried on it
- The type of oil
- The age and condition of the slab
If a dark mark is still there after several sensible treatments, the oil has gone too deep for surface cleaning. At that point grinding, resurfacing or a decorative overlay is a far better answer than escalating to stronger and stronger chemicals.
How do you prevent future oil stains?
Prevention is much cheaper than removal. To protect driveways and garage floors:
- Put a drip tray under anything that leaks
- Clean spills as they happen
- Keep absorbent material in the garage and shed
- Sweep regularly
- Fix vehicle leaks rather than living with them
- Keep the sealer maintained
- Do not leave oily tools sitting on the slab
- Use mats in the spots that always cop it
Check outdoor decorative concrete now and then. If water has stopped beading or the finish looks patchy, the sealer is near the end of its life and it is worth redoing before the next spill rather than after it.
When should you call a concrete professional?
It is worth getting someone out when:
- The stain covers a large area
- Several attempts have already failed
- The concrete has a decorative finish
- The sealer has been damaged
- Aggregate is coming loose
- The surface has changed colour
- There are cracks or other damage as well
- You are weighing up grinding, resurfacing or resealing
A professional can tell you whether the problem stops at the sealer or has gone into the concrete, which saves you working through a series of treatments that were never going to fix it and might permanently change the finish.
Get advice about stained or damaged concrete
Oil stains are easiest to deal with early. Absorb the spill, start with the gentlest method that suits the surface, and only move to stronger products once you have checked they are compatible with your concrete and its sealer.
If your driveway, garage floor or decorative concrete is still marked after a clean, CoastCrete can take a look and tell you whether repair, resealing or resurfacing is the sensible option.
Get in touch for an obligation-free quote.
About Richard Marsh
Founder · CoastCrete · 20+ years on the tools
Richard founded CoastCrete in Perth after a decade of pouring driveways, alfrescos and pool surrounds across the metro. He writes the articles, answers the calls, and runs the crew personally on every job — so what you read here is the same advice he gives clients on-site every week.
Read more articles by Richard →Common questions
What is the best thing to remove oil from concrete?
For a fresh spill, an absorbent material such as cat litter or baking soda followed by grease-cutting dishwashing liquid. For anything older or heavier, a concrete degreaser made for your type of surface will do far more than household products.
Does baking soda remove oil stains from concrete?
It works on small, recent spots and light residue on plain unsealed concrete. It absorbs surface oil and gives a little gentle abrasion. It will not shift an old stain that has soaked deep into the slab.
Can you remove old oil stains from concrete?
Often you can reduce them significantly with a poultice, which draws oil back out of the pores as it dries. A faint shadow may remain where the oil has discoloured the concrete itself, and very deep stains may need grinding, resurfacing or an overlay.
Will pressure washing remove oil from concrete?
Not on its own. Pressure washing clears loosened oil and cleaning residue but does not break oil down, so it works best after a degreaser. Use a wide spray on low pressure, especially on exposed aggregate, coloured or sealed concrete.
Does oil damage concrete permanently?
Oil rarely damages the structure of a slab, but it can permanently discolour it if left long enough, because concrete is porous and the oil soaks in. The staining is the issue rather than the strength of the concrete.
Should you hose down an oil spill on a driveway?
No. Water spreads the oil across a wider area and carries it into soil, gardens and stormwater drains. Cover the spill with absorbent material first, remove it, and only then clean the surface.