Recycling used motor oil keeps oil out of landfills and ensures that this oil is available for re-use, reconditioning, reprocessing or re-refining. From a purely environmental point of view, the best thing that the motor oil consumer can do is to buy a longer-lasting oil. In that way, less used oil is generated in the first place. Over 380 million gallons of used oil is recycled each year according to the U.S. EPA, which equates to over 50% of all motor oil purchased annually. Currently, used motor oil can be re-used or recycled one of three ways - reconditioning, reprocessing or re-refining. It is important to note that each process can be important in helping to manage the overall volume of used motor oil in the U.S.
Proper, modern Re-refining with careful feed and product quality control, as well as sophisticated processes can successfully treat used motor oil to remove impurities so that it can be used as base stock for new lubricating oil. In other words, with good design and process management the used oil can be re-refined into "new" oil, giving it a second life so it can be used for vehicle motor oil again.
Currently 14% of used motor oil is re-refined and the consumer demand for this product has not made re-refining economically efficient for oil manufacturers. The result is that in some cases re-refined motor oil may be more expensive than virgin motor oil, When purchasing re-refined motor oil make sure that the oil specifications for the product meet those required by your vehicle manufacturer.
In some industries, oil is filtered through a commercial filtration system or otherwise cleaned. This process helps remove insoluble impurities so the oil potentially can be used again and again. Although the cleaning process does not always bring the oil back to its original quality, such cleaning, when combined with replenishment of key additives, does extend the oil's life and use.