Where did that darn oil spot on the driveway come from? The car? The truck? Suzie's boyfriend's hotrod? Wherever it came from, it still has to be cleaned up. Bad oil stains, whether on the driveway or the street, are a health and safety concern. Management's inspector may write it up as a violation of the deed restrictions as noted in the association's CC&Rs.
Motor and hydraulic oils can really cause a mess on concrete, brick, and blacktop but the good news is that you can achieve excellent clean up results if you act quickly. Concrete is a dense surface but water and many other liquids can and do soak into the surface. Fresh oil stains will be a breeze to remove. The older oil stains, however, may be a far greater challenge.
Removing the fresh stain from the driveway will require a regular scrub brush, some liquid dish soap, and water. All you need to do is squirt some liquid dish soap onto the stain and add some water. Be sure to wet down the surrounding concrete as well. This will prevent oil released during the cleaning process from causing a secondary stain. Scrub the stain vigorously and add enough water to make a rich lather of soap.
The soap will emulsify the oil and lift it out of the concrete. If you simply rinse the driveway, the oil will pollute your yard or street. You may decide it is more environmentally responsible to blot up a majority of the dirty soap mixture with paper towels or a dry compound like cat litter and dispose of this in a certified landfill. There is a good chance your local waste collection service can accomplish this task for you.
DO NOT uses a wire brush to scrub the concrete. It can erode and scratch the concrete finish resulting in a permanent scar. Try using a standard nylon bristle scrub brush that can be purchased at a local grocery store. Some stains require several scrubbing attempts to completely remove all of the oil.
You can use the same method to attack older stains. If the concrete finish is quite smooth, you may have a great chance of success. Smooth steel troweled concrete, often used in garages, is highly resistant to oil stains. This type of finish, though, is unsuitable for exterior concrete. It simply is too slippery when it gets wet. Rough concrete finishes absorb oil rapidly.
If the old stains do not respond to the soap and water method, you can consider using a solvent like kerosene to help lift the stain. Solvents, however, are very dangerous to work with. The fumes from these products can ignite and cause serious harm to you and your home. If you decide to work with solvents, only do so after consulting with your local fire department's fire prevention officer.
Some people have had success lifting oil stains using muriatic acid. But keep in mind that this chemical, even when mixed one part acid to ten parts water, can and will dissolve some of the cement paste at the surface. Couple this with scrubbing, and you very well may alter the appearance of the concrete once it dries.
Clean concrete can be treated to help minimize the penetration of oil and water that contains dirt and pigments. Some of the best products are clear water and oil repellents that contain silane and siloxane ingredients. These chemical solids help block the tiny pores in concrete to stop water from entering and soaking into the concrete. The silane and siloxane products allow the concrete to breathe. This is very important for concrete that is subjected to freezing temperatures. The clear repellents are easy to apply and dry clear.
There are several other cleaning products on the market, although some can be expensive. V-Seal V-Scrub Concrete Cleaner is a general purpose blended powder cleaner designed to cut through stubborn grease, grime, oil, and most other dirt that accumulates in and on concrete surfaces and is EPA compliant. Look for this product on the Web at www.vseal.com or call 877-738-7325.
EOS (Endur-O-Seal) Oil X-Out is another product that is a biodegradable, severe duty concrete cleaner for oil-saturated slabs. Recommended for auto dealerships, truck shops, diesel engine maintenance facilities, fab and machine shops, bank drive through area's, parking lots, driveways, patio's and many more.
The polluted areas of the slab are saturated with EOS Oil-X-out and if the build up of oil and grease are considered heavy then apply an extra heavy application of EOS G-A Granule Accelerator and scrub it into the heavy build up. This may have to be repeated until grease build up can be pressure washed away. (Pre-scraping the floor prior to using EOS Oil-X-Out is highly recommended to remove heavy build-up.) With no standing water, apply a saturating application to slab, hand cast a liberal application of EOS G-A Granule Accelerator over saturated surface, allow products to penetrate concrete and emulsify the internal oil, and to react with contaminants for up to 4 hours allowing it to purge concrete clean. Pressure wash the surface until clean. Use an all Poly hand pump sprayer to apply. EOS products can be located at www.concretesealants.com/oilxout_cleaner.htm.
Revive-a-Drive is another cleaning agent that can be purchased at Wal-Mart. This is a water-based, non-hazardous cleaner that penetrates the concrete surface to pull up tough grease and oil. Revive-a-Drive will not harm painted surfaces, shrubs, or vegetation. Some people have had some luck with CLR, the cleaner for calcium, lime, and rust, and a little elbow grease. If you're up to a little work, CLR may be purchased at Walgreen's, Home Depot, or Lowe's.
Once you've gotten the concrete clean, be sure to seal it as an added protection against stains. Concrete sealers penetrate up to an inch into the porous surface, forming an impervious barrier. Sealing not only helps prevent water damage, but it also helps keep stains from soaking into the concrete. Before sealing, the surface must be completely clean and totally dry.
Sealers come in a variety of sheens and looks. Test a small, inconspicuous area before sealing the whole slab. Apply the sealer following the manufacturer's instructions with a paint roller or a garden sprayer. The concrete will need to be resealed every few years if it's exposed to weather. Different sealers have different application methods and precautions. Be sure to read the label carefully.
VSeal and EOS carry concrete sealants as do Interstate Products, Inc. (online at www.interstateproducts.com/concrete_sealer.htm) and Moxie International (www.moxie-intl.com/1600-BENEFITS-AND-ADVANTAGES.htm). You may have to do a little more research if your oil and grease stains are really stubborn and the above-referenced products don't work well enough for you. That said, there is an abundance of information and possible solutions to be found on the internet.