Scientists at Global Resource Corporation can now turn plastic back into oil using a giant microwave:
Key to GRC’s process is a machine that uses 1200 different frequencies within the microwave range, which act on specific hydrocarbon materials. As the material is zapped at the appropriate wavelength, part of the hydrocarbons that make up the plastic and rubber in the material are broken down into diesel oil and combustible gas.
GRC's machine is called the Hawk-10. Its smaller incarnations look just like an industrial microwave with bits of machinery attached to it. Larger versions resemble a concrete mixer.