There are many practical uses for used motor oil. A primary use is to re-refine it into a base stock for lubricating oil. This process is very similar to the refining of crude oil. The result is that the re-refined oil is of as high a quality as a virgin oil product. In fact, re-refining used oil takes from 50 to 85 percent less energy than refining crude oil.

A secondary use of the used oil is to burn it for energy. Large industrial boilers can efficiently burn the used oil with minimum pollution. As a result some used oil is sent to power plants or cement kilns to be burned as fuel. On a smaller scale small quantities of used oil are burned in specially designed heaters to provide space heating for small businesses.