Start by watching the video below
In the video, a Japanese man converts plastic waste into usable oil and fuel using a machine that thermochemically decomposes the plastic in a process known as pyrolysis.
Pyrolysis works by thermochemically breaking down material at temperatures above 350 degrees Celsius in the absence of water. This not only physically melts down an object, but also changes its chemical composition so that, in the case of plastic waste, it reverts back into boiling liquid and eventually gas.
Source: http://www.sciencealert.com/holy-crap-watch-this-guy-turn-plastic-back-into-oil
