There are many practical uses for used motor oil. A primary use
is to rerefine it into a base stock for lubricating oil. This process
is very similar to the refining of crude oil. The result is that
the rerefined oil is of as high a quality as a virgin oil product.
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.