a method of and apparatus for sorting plastic items is disclosed . the method comprises the steps of transmitting polychromatic light from a source through each individual item ; detecting the quantity of light of a first color passing through each individual item with a detector opposed to the source as a stream of the items is successively directed past the source and the detector ; detecting the quantity of light of a second color passing through each individual item with the detector , wherein the second color is different from the first color ; and selectively removing individual items from the stream , the removal being based upon a comparison of the quantity of light of the first color detected and the quantity of light of the second color detected .