The definition of recycling vs. re-refining has changed over the years. To better help you understand the difference CEP has attempted to define each. Recycling of used oil can mean many things, anywhere from burning the used oil as in boilers or as in marine diesel fuel, filtering the oil and reselling, to re-refining. The term recycled oil is often used for oil that has been filtered and then rebottled (reconditioned oil). This type of oil has no API certification and has limited uses. Reconditioned oil is simply using commercial filtration systems which remove insoluble impurities. This method, however, does not remove any of the soluble contaminants. This oil is generally used for fuel. Reconditioned oil is not suitable for use in automobiles. Re-refining is a process that has been developed over many years. It removes all impurities, soluble and insoluble, and returns the oil to the same state as virgin base oil. Re-refined oil is equal to or better than some virgin base oils and is suitable for use in automobiles. The re-refining process is less severe than the refining of crude oil and uses less energy because of this it has a smaller carbon foot print. Motor oils do not wear out and can be re-refined several times while reconditioned oils that are used for fuels have a one-time use.