Oil and grease stains don’t just make a floor look bad, they can also cause falls, ruin your shoes and get tracked into the house. If you want to finish your floor with a coating, it is important to get rid of oil deposits for a good bond. Although, solvent-based remedies are harmful to the environment and can damage the concrete surface, small spots or spills can be removed with a strong detergent, a sponge and a scrub brush. Also, sawdust and other absorbent materials can remove standing oil but they do nothing about the oily stain left behind.

There are different chemical methods for removing oil or grease from concrete. A more aggressive method is the use of a commercial concrete degreaser or cleaner, a concentrated alkaline soap that is scrubbed into the surface of the concrete. The soap acts like ball bearings, it loosens up the oil to allow easier removal. The disadvantage is that most degreasers do not actually break down the oil, so they might not work well on heavily contaminated concrete or concrete that has been contaminated for a long time. In addition, they are more effective on porous concrete rather than concrete with a hard or dense finish.

Another treatment that is common for removing oil stains from concrete is a poultice. A poultice, used primarily on small, stubborn stains, is made by saturating an absorptive material with a strong solvent and then smearing the material over the stain. The poultice is then covered with plastic and the process of osmosis will then take over. The solvent breaks down the oil while the absorptive material sucks it out of the concrete.  But, this process usually takes a lot of time and it may not be cost-effective or even that practical for removing large stains.

The most recent advancement used in the removal of oil stains from concrete is the use of special single-celled microorganisms that thrives on crude oil and its derivatives, these microorganisms will eat the oil stains up like candy. Enzymes and oxygen then digests the oil and later turn it into carbon dioxide and more microorganisms. When the food source, which is the oil, is gone, the microorganisms die, thereby leaving the concrete patio clean and oil-free. This method is the same technology used in cleaning beaches and waterways whenever there is a large oil spillage. Two of the sources for these microbial cleaners are KT and ESI Microbial Products.