How to Remove Oil Stains From Concrete: A Step By Step Guide

Oil stains on concrete are very common, and if left untreated for prolonged periods, they're one of the most difficult types of stains to remove from concrete floors. Some oil stains may be superficial, while others can penetrate deep into the surface.

Oil stains can be found on garage floors, industrial settings, equipment repair shops, and automotive plants. They're also common in grocery stores, restaurants, and food processing facilities.

Oil's chemical properties, combined with the porous nature of concrete (even sealed or densified concrete remains somewhat porous) means that it absorbs quickly and clings tightly in all the nooks and crannies. Concrete cleaning products and mild detergents are seldom enough to remove an old oil stain, while some harsher products risk causing discoloration or damage to concrete floors.

Here, we're discussing professional cleaning methods for removing oil stains from concrete - whether on a warehouse floor or residential driveway.

What Makes Oil Stains So Stubborn?

Oils, whether natural or synthetic, are hydrophobic, meaning they repel water. This property makes oil stains resistant to water- and water-based cleaning solutions - instead requiring a solution with emulsifying properties that can dissolve the oil and remove it from surfaces.

Beyond that, oil also has a low surface tension, which allows it to spread out thinly over surfaces and penetrate deep into porous materials like concrete. Paired with concrete's porous structure, oil becomes even more difficult to extract without specialized cleaning tools and techniques. For oil with a higher viscosity, its thick and sticky texture allows it to adhere more strongly to surfaces.

Identifying Oil Type Before Removal

Most of the time, your client should be able to confirm the type of oil that caused the stain. If they can't, the location of the stain can sometimes be a giveaway. For example, if the stain is near a parked car, it's probably motor oil, whereas a stain near a kitchen is likely cooking oil.

How to Remove Oil From Concrete

There are a couple of types of products that work well for removing oil from concrete: stain removers and degreasers. Before getting into the step-by-step process for each, here are some important items to remember:

• Use appropriate personal protective equipment (PPE): Oil and some cleaning chemicals can be harmful to skin, eyes, and lungs. Before initiating the cleaning process, wear gloves, eye protection and a respirator to avoid contact and inhalation risks.
• Be mindful of how you discard materials: Oil-soaked rags, absorbents or cleaning solutions should be disposed of responsibly according to local regulations.
• Don't overpromise: It's important to communicate realistic expectations with customers. While you can do your best to deliver results, complete removal of some oil stains - especially long-standing ones that have penetrated deep into the concrete surface - may not be possible.

How to Remove Fresh Oil Stains

For fresh surface oil spills that have yet to penetrate, you can try the following:

1. Dilute 4 parts PROSOCO Consolideck® Cleaner/Degreaser to 200 parts water.
2. Apply the solution to the affected area with a stiff brush or low-pressure spray.
3. Rinse away with clean water.

Note: A cleaner or degreaser can be effective for a fresh oil spill or surface stain but is not recommended for embedded oil or grease. If you're dealing with an old, stubborn stain, follow the recommendations outlined below.

How to Remove Old Oil Stains

Method 1: MR SURFACE Oil Stain Remover

1. Wet the area to be cleaned with water and liberally apply MR SURFACE Oil Stain Remover undiluted using a handheld or pump-up sprayer.
2. Agitate the floor periodically to help disperse the microbes and break down the oil for faster digestion. Be sure to keep the floor moist while the bacteria in MR SURFACE are working. Note: The time needed for cleaning will vary between 30 minutes to several hours. Keep in mind that some floors have been exposed to oil for many years and may need a longer time for the microbes to completely digest all the contamination.
3. Rinse the floor toward a drain or use a wet/dry vacuum to remove the microbes, then dry the floor thoroughly.

Method 2:PROSOCO Consolideck® Oil & Grease Stain Remover

1. Apply PROSOCO Consolideck® Oil & Grease Stain Remover as a poultice to the floor, following label directions.
2. Allow the poultice to dwell for 24 hours or longer until fully dry. As the poultice dries, it will pull the oil stains from the concrete.
3. Use a putty knife to break and scrape the poultice from the floor. Thoroughly vacuum the area to remove the debris.
4. Repeat steps 1-3 if needed. Note: This method sometimes makes the treated area cleaner than the rest of the floor, so you may notice a clean white or light-colored spot surrounded by untreated/dirty concrete.

Planning on Applying a Coating?

If you are planning on coating the concrete after treating an oil stain using the methods above, our experts recommend additional steps to degrease the area.

Grind or shot-blast the surface to obtain a suitable profile that promotes coating adhesion and use an oil-tolerant primer. For more information or product recommendations for your job site, contact a member of the Jon-Don Concrete Team at 800-556-6366.

Oil Removal From Concrete FAQs

If you still have questions, whether you're a professional or a homeowner looking for a quick solution, here are some answers to FAQs about how to clean oil stains:

Can Cat Litter, Dish Soap or Baking Soda Remove Oil From Concrete?

While some DIY solutions may be effective on fresh oil stains, using the proper cleaning products can produce the best results - especially for set-in stains.

Before reaching for one of these quick, household solutions, remember:

• Clay-based cat litter is highly absorbent and may soak up fresh oil spills before they penetrate the concrete.
• Dish soap can be somewhat helpful on smooth concrete surfaces to help cut through grease, but may not be strong enough for set-in stains.
• Baking soda is mildly absorbent and has some cleaning power, but it's not the best choice for oil stains on concrete.

Instead, reach for the products mentioned in the cleaning guide above for a professional finish every time.

Is a Pressure Washer an Effective Tool for Oil Stain Removal?

While giving a stained concrete surface a pressure wash can be effective, water alone cannot break down stain-causing molecules found in oil. Furthermore, using a powerful stream on damaged concrete can make matters worse. For the best results, use an industrial-grade stain remover that's specially formulated for concrete.

Learn How to Clean and Restore Concrete Surfaces

Sometimes after a tough oil removal job, concrete surfaces need to be re-prepped and polished or have a new coating installed. For a professional finish, brush up on your concrete polishing, epoxy and coatings installation skills in one of Jon-Don's many concrete classes.

For upcoming sessions and to sign up, see our concrete classes page.

For more concrete surface preparation tips and guides, visit our Concrete Surface Prep & Epoxy Technical Tips page.