Some used oil is refined and used again and some is burnt up.
http://www.recycleoil.org/
http://www.recycleoil.org/recycle_oil_process/usedoil.html
My grandpa used to dump his dirty motor oil at the base of a Catalpa tree. He got tired of all the caterpillars eating the leaves. He had no more problems after that. I guess the tree soaked it up and the caterpillars didn't like the taste of motor oil. Definitely not good for the environment.
http://www.recycleoil.org/
http://www.recycleoil.org/recycle_oil_process/usedoil.html
My grandpa used to dump his dirty motor oil at the base of a Catalpa tree. He got tired of all the caterpillars eating the leaves. He had no more problems after that. I guess the tree soaked it up and the caterpillars didn't like the taste of motor oil. Definitely not good for the environment.