Oil is not a surface stain. By the time you see it, it has soaked into the pores of the concrete, which is why scrubbing and pressure washing so often leave a shadow behind. Removing it properly means drawing the oil back out, not blasting at the top of it.
How you do that depends almost entirely on one thing: how long it has been there.
If the spill is fresh
Do not reach for the hose. Water spreads oil sideways and pushes it deeper, turning a coin-sized drip into a dinner-plate stain.
Cover it with something absorbent instead — cat litter, sawdust, sand, or a commercial absorbent granule. Cheap clay-based cat litter works as well as anything. Pile it on generously, then crush it underfoot to work it into the surface texture, and leave it. Twenty minutes will help; overnight is better.
Sweep it up and check what is left. Often a fresh spill treated this way leaves almost nothing behind, and the rest comes out with a degreaser.
If it is days or weeks old
Once oil has been absorbed but not fully set, a degreaser plus mechanical agitation will usually shift it.
Wet the area, apply an alkaline concrete degreaser and let it dwell for the time on the label — dwell time matters far more than scrubbing effort, and cutting it short is the most common mistake. Then agitate with a stiff-bristled broom, working in two directions. Rinse with hot water if you can. Heat thins the oil and helps it release.
Expect to repeat this. Two moderate applications almost always beat one aggressive one, and repeating is gentler on the concrete than increasing pressure.
If it is old and set in
This is where most DIY attempts stall, and where the method that actually works is barely mentioned online.
You need a poultice — a paste that sits on the stain, dissolves the oil, and then draws it upward as it dries. It is a reversal of how the stain formed, and it is the only reliable way to lift oil out of deep concrete.
- Mix an absorbent powder with a solvent or strong degreaser until it is the consistency of thick peanut butter. Diatomaceous earth, powdered chalk or hydrated lime all work.
- Spread it over the stain about 10mm thick, extending 25mm past the edges.
- Cover with plastic sheet, taped down at the edges. This slows evaporation so the solvent has time to work.
- Leave for 24 hours, then remove the plastic and let the poultice dry out completely — usually another day. This drying phase is what pulls the oil up.
- Scrape off the dried powder and rinse.
A deep stain may take two or three cycles. It is slow, and it is far more effective than anything you can do with a wand.
What does not work
- Pressure alone. High pressure removes the top layer of concrete along with the top layer of stain. You get a lighter patch and a slightly eroded surface, and the oil below is untouched.
- Bleach. It does nothing to oil. It is for organic growth, which is a different problem entirely.
- Petrol, thinners or brake cleaner. These dissolve oil and then carry it deeper into the slab. They are also a genuine fire risk on a driveway and they damage surrounding surfaces and plants. Not worth it.
- Dish soap on an old stain. Fine for a fresh drip. It has no ability to lift oil that has already penetrated.
Two things that make this harder in Brisbane
Heat. Concrete in full Queensland sun gets hot enough to thin oil considerably, and thin oil travels. A spill on a 35-degree afternoon penetrates faster and deeper than the same spill in July. If it happens in summer, treating it that day rather than that weekend makes a real difference.
Humidity. Poultices rely on drying to work, and during the wet season they simply take longer. Give the drying phase more time than the instructions suggest, and don’t attempt it with rain forecast.
When it will not come out completely
Worth saying plainly: some stains are permanent. Oil that has been sitting on porous, unsealed concrete for years — under a car that has leaked for a decade, say — has penetrated further than any poultice will reach.
In those cases the realistic outcome is significant lightening rather than removal. Anyone promising a perfect result on a decade-old stain without seeing it is guessing. The honest options at that point are resurfacing, or accepting the improvement.
Afterwards
Concrete that has just been degreased is unusually porous — the treatment strips it back. That makes it the ideal moment to consider sealing, which gives you time to lift future drips before they penetrate. We cover the timing and the trade-offs in our guide to sealing after cleaning, and it is worth reading before you buy a product, because sealing a slab that is still holding moisture causes a milky haze that is worse than the stain.
If the stain is beyond what you want to tackle, or you would rather not risk making it worse, see what driveway cleaning involves or request a free quote. We will tell you honestly whether a stain will lift or only lighten before we start.
