How to remove oil stains from a driveway

An oil stain on the driveway is one of the most common — and most stubborn — marks we deal with on Canberra concrete. The good news is that most of them can be lifted with the right approach, and this guide walks you through exactly what works on both fresh spills and old, set-in stains.

Why oil is so hard to shift

Concrete looks solid, but it's actually full of tiny pores. When oil lands on it, capillary action pulls the oil down into those pores, and the longer it sits the deeper it travels. That's why a spot you wiped weeks ago still shows a dark shadow — the surface is clean but the oil below isn't. The single most important rule follows from this: act fast on fresh spills. A puddle dealt with in the first hour is far easier than the same oil after it's had a week to soak in.

Whether your concrete is sealed also makes a big difference. Sealed concrete resists oil and cleans up much more easily, because the sealer blocks the pores. Bare, unsealed or worn concrete is porous and stains far deeper.

Fresh spills: absorb first

For a spill that's still wet, don't reach for the hose yet. Work through these steps:

1. Soak up as much excess oil as you can with rags or paper towel — blot, don't smear.
2. Cover the stain with an absorbent material. Cat litter, baking soda, sawdust or plain sand all work well.
3. Leave it to draw the oil out for several hours, or ideally overnight.
4. Sweep up the used absorbent and dispose of it properly.

For a light or recent stain that remains, scrub it with hot water and dish soap or a grease-cutting detergent, then rinse. That's often all a fresh spill needs.

Set-in and older stains: degrease

Once oil has been sitting for a while, soap won't cut it. You need a proper alkaline concrete degreaser. The method is simple:

• Apply the degreaser to the stain per the label.
• Let it dwell — this is where it breaks the oil down, so don't rush it.
• Agitate with a stiff-bristled brush to work it into the pores.
• Rinse thoroughly.

Stubborn stains often need two or three rounds. Each pass pulls a little more oil out, so don't be discouraged if one application only lightens it.

The poultice method for deep old stains

For an old stain that has soaked deep into the concrete, a poultice is the most effective home fix. Mix a degreaser or solvent with an absorbent (such as sawdust or a fine powder) into a thick paste. Spread it generously over the stain, cover it with plastic, and let it dwell — anywhere from a few hours to a full day. As it slowly dries, the paste draws the oil back up out of the pores. Remove it, and repeat if the stain is very deep. It's slow, but it reaches oil that surface scrubbing never will.

Where the pressure washer comes in

Here's the part people get wrong: a pressure washer used on its own does not remove oil — it tends to spread it, blasting a concentrated stain into a wider, faded smear. Oil has to be broken down chemically first. So the correct order is always to degrease first, let the product do its work, then pressure wash to flush the loosened grime away. A hot-water pressure washer works best of all, because heat softens oil far more effectively than cold water. This is a big reason a professional clean lifts oil that a hired cold-water unit leaves behind — see what a professional clean costs if you're weighing it up.

What to avoid

• Petrol, paint thinners and raw solvents poured on the slab. They're a genuine fire risk, they can damage any sealer, and they often just spread the stain further.
• Chlorine bleach. It does very little to oil and it harms your plants and lawn where the runoff lands.

Stick to purpose-made concrete degreasers — they're safer and they actually work.

An honest word on results, and resealing

Most oil stains improve dramatically once you degrease properly. But be realistic: some very old stains leave a permanent shadow or discolouration even after every trace of oil is gone. That's the concrete itself that has changed colour, not remaining oil, and no amount of scrubbing brings it back.

Once the driveway is clean, it's worth resealing. A fresh seal helps the concrete resist future oil, and it makes the next clean far easier. While you're at it, oil is rarely the only mark on a driveway — our guide to rust, efflorescence and tyre marks covers the other common culprits.

A note for Canberra driveways

Local conditions matter here in the ACT. Degreasers rely on a chemical reaction, and cold weather slows that reaction right down — so tackling a stain on a mild, warmer day gives you noticeably better results than working through a frosty Canberra winter morning. In the other direction, hot summer days soften bitumen and oil, so it's easy to track fresh oil onto the driveway when the mercury climbs. A quick blot and absorb whenever you spot a spill goes a long way.

FAQs

How do you get old, set-in oil stains out of concrete?

Old stains have soaked deep into the pores, so surface scrubbing won't reach them. The best home method is a poultice: mix a concrete degreaser or solvent with an absorbent into a paste, spread it over the stain, cover it with plastic and let it dwell for several hours to a day, then remove it. As the paste dries it draws the oil back up out of the concrete. Repeat the degrease-and-poultice cycle for stubborn stains. Even then, a very old stain can leave a faint shadow that no longer contains oil but has permanently discoloured the surface.

Does a pressure washer remove oil stains?

Not on its own. A pressure washer used straight over an oil stain tends to push the oil around and spread it into a wider, lighter patch rather than lift it out. The oil has to be broken down chemically first. Apply a degreaser, let it dwell and agitate it, then pressure wash — ideally with hot water, which softens oil far better than cold — to flush away the loosened grime.

Do Coke or WD-40 remove oil from a driveway?

These are popular internet tricks but they do very little on a real oil stain. Soft drink has no meaningful degreasing power, and WD-40 is itself an oil, so you're adding oil to the problem. A purpose-made alkaline concrete degreaser is designed to break down and lift oil from porous concrete, and it will outperform both by a wide margin.

Will the stain come out completely?

Most oil stains improve dramatically with proper degreasing, and fresh or recent ones often disappear entirely. Older, deeply soaked stains can leave a faint shadow or discolouration in the concrete even after all the oil is gone. We're always honest about that up front rather than promising a perfect result on a stain that has been there for years.