TL;DR
Garage floor degreasing is governed by stain age more than by effort. Fresh oil sits near the surface and usually comes out. Oil that has been soaking into bare concrete for years has penetrated below where any cleaner reaches, so it lightens rather than disappears. The service typically covers clearing, absorbent lifting, degreaser application with dwell time, agitation, and rinse or extraction.
Why Concrete Holds Oil
Concrete looks solid and behaves like a sponge.
It is full of connected pores, and oil wicks into them by capillary action. A drip that landed last week is still mostly near the surface. A drip from three years ago has migrated millimeters down, and a surface cleaner can only work on what it can contact.
Sealed or coated concrete behaves completely differently, because the coating stops the oil from getting in at all. On a coated floor, a spill sits on top and wipes up. That difference is the single biggest variable in what results you should expect.
So the first question any provider should ask is whether the floor is bare, sealed, or coated -- and if the answer is not obvious, a water drop test settles it. Water that soaks in and darkens the concrete means bare. Water that beads means there is something on top.
What Does Garage Floor Degreasing Cover?
It typically covers clearing the floor area, applying absorbent material to lift what has not soaked in, applying a degreaser and allowing dwell time, agitating with a brush or floor machine, and rinsing or extracting the residue. Multiple applications on heavy stains are usual. Coating, sealing, and crack repair are separate services.
Whether the floor is rinsed or extracted depends on drainage. Garages often have none, so many providers use a wet vacuum or extraction rather than flushing water toward the door.
The Sequence That Actually Works
Clear and dry-sweep first. Loose grit turns into slurry the moment degreaser goes down, and slurry protects the stain from the cleaner.
Absorbent lift. For any spill that is still wet or tacky, an absorbent granule, clay-based product, or even fine cat litter pulls out what has not yet penetrated. Left down and worked in with a foot or brush, then swept up. This step gets skipped constantly and it does more than anything that follows.
Degreaser with dwell time. An alkaline degreaser or a citrus-based product goes down and stays wet on the stain. Dwell time is the mechanism -- the product has to work into the pore structure. Letting a degreaser dry out on concrete stops it working, so heavy stains are often covered or re-wetted.
Agitation. A stiff brush or a floor machine works the product in. This is scrubbing to distribute the chemistry, not scrubbing to remove the oil by force.
Rinse or extract. Then repeat on anything that improved but did not finish. Two or three applications on an old stain is normal.
Poultice for the worst. A poultice -- an absorbent paste spread over the stain, covered, and left for a day or more -- draws oil back up out of the pores as it dries. It is the most effective approach on deep old stains and the slowest, which is why it is usually reserved for a few specific spots.
What Results to Expect
Honest expectations by stain age:
Days old. Usually comes out completely with absorbent lift and one degreaser pass.
Weeks to months old. Usually improves dramatically. A faint shadow may remain in unsealed concrete.
Years old. Lightens noticeably, often substantially, but a visible mark commonly stays. The oil below the surface is not reachable.
Decades old, or repeated in the same spot. Improves, but expect a permanent shadow. At that point the practical answer is a coating rather than more cleaning.
That last point is worth taking seriously. Where a floor has years of accumulated staining, epoxy or polyaspartic coating both hides it and prevents future absorption -- but coating requires proper surface preparation, usually grinding, and a clean dry substrate. It is a separate trade and a separate cost, and degreasing is often the first step in that process rather than an alternative to it.
Other Stains on a Garage Floor
Oil is the headline, but garage floors collect several other things that need different chemistry.
Rust from metal furniture, tools, or road salt needs an oxalic or specialty rust remover rather than a degreaser. Do not use it alongside any bleach-based product.
Battery acid etches concrete and the damage is permanent. Neutralize any spill and expect a mark.
Tire marks are rubber and plasticizer transfer, and respond to a citrus or solvent degreaser.
Paint drips need the right approach for the paint type; a solvent that works on latex may do nothing to enamel.
De-icing salt residue leaves a white film and can cause spalling over time. It rinses off, but the surface damage does not reverse.
Efflorescence, the white powder that migrates up through the slab, is a moisture indicator rather than a stain. Cleaning removes the deposit; the moisture path is a separate question.
Never combine products. Mixing an acid rust remover with a bleach-based cleaner produces chlorine gas, and a garage with the door closed is exactly the wrong room for that. One product at a time, with the door open.
Safety and Runoff
Degreasers are strong, garages are enclosed, and there is often no drain.
Ventilation means the garage door open, and ideally a fan. Gloves and eye protection are standard. Any product that says to avoid skin contact means it.
Runoff carrying oil and degreaser should not go to a storm drain. Extraction with a wet vacuum, or absorbent capture, is the responsible approach and is what most professional operators do. If you are hiring, asking how they handle the wastewater tells you how carefully they work.
Coated floors need pH-appropriate products. Aggressive alkaline degreasers can haze or damage some coatings, so a coated floor is cleaned with a neutral cleaner unless the coating maker says otherwise.
When to Book It
Degreasing is usually booked in one of four situations: as part of clearing out a garage, before applying a coating, before selling a home, or after a specific spill or leak.
It is nearly always done alongside a garage clean, because the floor cannot be treated until the contents move. Bundling the two is more efficient than two visits.
Sequence-wise, degreasing comes after the garage shell is dry-cleaned and before anything goes back on the floor. If a driveway is also being washed, it usually happens in the same visit, though the methods differ -- driveway pressure washing has drainage and open air on its side. The general order for hardscape work is in the exterior surface cleaning guide.
Timing matters if a coating follows: concrete must dry fully before any coating goes down, which typically means several days depending on humidity.
FAQ
Can old oil stains be removed from a garage floor?
They usually lighten substantially but often will not disappear. Bare concrete is porous, so oil that has soaked in over years sits below where any cleaner reaches. A poultice draws some of it back up, and multiple degreaser applications help, but a shadow commonly remains on decades-old staining.
What is the best way to treat a fresh oil spill?
Cover it with an absorbent granule or clay-based product immediately, work it in gently, leave it to draw for a few hours, and sweep it up before applying a degreaser. Lifting what has not yet penetrated is the step that determines whether the stain becomes permanent.
Does pressure washing remove oil from concrete?
Not on its own. Water spreads oil rather than lifting it, so pressure alone tends to widen the stain. A degreaser with dwell time does the chemical work; pressure or agitation afterward removes the loosened residue. Inside a garage, extraction is usually preferred over a rinse because there is no drainage.
Is degreasing safe on a coated or epoxy garage floor?
Use a neutral cleaner unless the coating manufacturer says otherwise. Aggressive alkaline degreasers can haze or degrade some coatings. The advantage of a coated floor is that oil sits on the surface rather than soaking in, so it usually wipes up with a mild cleaner and no dwell time at all.
Should I coat the garage floor after degreasing?
It is worth considering if the floor has years of staining, since a coating hides existing marks and prevents future absorption. Coating requires proper surface preparation, usually grinding, plus a clean fully dry slab, so it is a separate trade and a separate cost. Degreasing is often step one of that process.
Is it safe to mix degreasers with other cleaners?
No. Combining an acid rust remover with a bleach-based product produces chlorine gas, and an enclosed garage is the worst place for that. Use one product at a time, open the garage door for ventilation, rinse or extract between products, and wear gloves and eye protection.
Results depend on how long the stains have been there and whether the slab is sealed, so a quick look sets expectations. Otesse is local, background-checks its crews, prices upfront with no hidden fees, and books online -- see home cleaning services or get a quote. Every property is different, so the real number depends on size, condition, and what you want covered.