How to Remove Oil Stains From a Concrete Driveway
While prevention is always the best approach for concrete oil stains, it’s not always feasible to keep leaky vehicles off of exterior concrete surfaces. At Craftsman Concrete, we get more calls from customers about stains left by leaky delivery or construction vehicles than anything less. Regardless, fresh oil spills are always easier to address and will offer better results than stains that have been allowed to penetrate into the concrete.
REMOVING FRESH OIL STAINS FROM CONCRETE
For a fresh oil stain, the first step is to clean excess oil from the surface. On smooth surfaces such as polished concrete, a rag with dish soap may be used. On rough or broom finished concrete, a sweeping compound, sawdust, or even kitty litter may be used to absorb excess contamination.
Once the excess oil has been removed by the cat litter or other absorbant, we suggest trying diluted dish detergent with a stiff nylon brush to remove the remaining contamination. On very fresh stains, this is often enough to resolve the stain.
DIY Home Remedies for Removing Oil Stains on Concrete
If this doesn’t work, there are a number of home remedies that people stand by. A quick search on Youtube will turn up people using everything from powdered laundry detergent to gasoline and even soda. Just keep in mind, while many of these solutions will clean oil stains on concrete, they can often etch and degrade the underlying concrete in the process. While this may be okay for a concrete driveway or untreated garage floor, most of these solutions are not acceptable for decorative concrete surfaces.
Due to its absorbent nature, baking soda is a logical oil stain remover. Most proponents of this solution suggest mixing baking soda with acetone to create a paste and then allowing that to dry on the oil stain. This type of solution for removing oil is called a poultice, which is a common solution for pulling unsightly oil stains from concrete. Poultices excel on that have been allowed to set into the concrete as their desiccating properties pull the oil from deeper below the concrete surface than other solutions.
However, its alkaline pH may cause it to react with concrete and create unexpected outcomes. While baking soda is only a weak base, concrete is quite reactive when exposed to buffered liquids, and therefore this should only be tried on non-decorative concrete such as a standard sidewalk, driveway or unfinished garage floor.
While gasoline appears to clean oil stains, it will leave a persistent odor in the concrete that will take a very long period of time to dissipate. Further, its flammable nature makes it unsafe to use as a concrete cleaner and therefore is not something that we have tried. We highly recommend that no one attempt this method of oil stain removal.
While laundry detergent is also effective at removing oil stains, it only really removes oil from the most superficial surface of the concrete. This method takes a lot of elbow grease, and stains are known to reappear days later as oil trapped deeper into the surface is transported to the top of the concrete. Further, laundry detergent can be quite harsh on concrete, leaving an etched surface. While we understand the allure of a product that’s readily available, laundry detergent is generally less effective than dish detergent or a simple degreaser at removing oil stains on concrete. Therefore, we do not recommend this method, especially not for decorative concrete surfaces.
Soda is an effective concrete cleaner because it contains phosphoric acid. The acid eats the surface of the concrete taking any surface contaminants with it. While it will leave concrete looking cleaner, stains are likely to reappear and its abrasive nature makes it unsuitable for decorative concrete.
Dish soap is a simple surfactant and the most logical of the at-home remedies to an oil stain. While it must be diluted and will not be very effective for deeply set stains, it will be the least harsh on the existing concrete surface. Dilute dish soap can generally be used on all decorative concrete surfaces to remove oil stains without the risk of any ill effects.
Specialty Oil Removers
SIMPLE GREEN AND OTHER DEGREASERS
The most common specialty oil remover is the degreaser simple green. While simple green is only effective at removing fresh oil stains from concrete, it’s pretty gentle on outdoor concrete and can be applied to large areas. Further, it’s inexpensive and can be easily sourced at any hardware or auto parts store. Even still, it should not be used on decorative concrete finishes.
Due to their desiccating nature, a poultice is what we most commonly use for removing oil stains. While there are many recipes for a homemade poultice (from cat litter to baking soda), we have not found one that is both effective at removing oil stains and doesn’t cause some damage to concrete.
For most oil stain removal, we use Prosoco Oil and Grease Remover. It’s a poultice designed specifically for decorative surfaces, and only slightly lightens the area around the stain. Further, it will remove the stain deep into the concrete slab, reducing the chance that it will reappear necessitating an additional application.
MICROBIAL OIL REMOVERS
The newest type of oil remover, these products contain a microbe that digests grease stains without causing any deleterious effects to the concrete surface. While this may sound great, they have one giant downside—they work very slowly. Microbial removal generally takes around a month, while a good quality poultice takes about 12 hours.
Long application time withstanding, they’re still commonly used on decorative concrete floors because of their gentle nature. For pigmented floors and other complicated applications, these products are the only safe method of removing oil stains.
How to Remove Oil Stains From Polished Concrete
While polished concrete floors are less susceptible to staining than untreated concrete, they can stain if oil is allowed to sit on the polished surface. In this circumstance, home remedies such as laundry detergent or baking soda can’t be used to remove an oil stain as they may etch, discolor or otherwise damage the concrete surface. Instead, we suggest using a specialized poultice or enzyme product that is intended specifically for polished concrete floors.
Again, our favorite poultice is the Prosoco Oil and Grease Stain Remover. It minimally lightens the concrete around the stain, which is ideal for this use case. This product is also affordable, works quickly, and is readily available from online retailers.
The Ameripolish Microbial Oil-Ingester is a commonly used product on polished concrete floors as it won’t damage or discolor the concrete. Further, its safe for pigment-treated floors. However, as this product works by microbial action, it can take weeks for the stain to be fully digested. It also requires that water be sprayed on the stain daily during the removal process and that the stain be covered with plastic.
Looking for More Information about Stained Concrete Floors?
See our stained concrete page for links to articles about the types of stained concrete floors, galleries, and other content. As always, give us a call for a free consultation.