Electromagnetic radiation is projected through various types of plastics materials such as plastic containers. The readings from the electromagnetic radiation transmitters are received by a sensor array. Plural readings are taken from each plastic bottle as it passes under the sensor. The measurements from the sensor array output are then fed into a computer. The materials are then separated into three classes. The first class contains polyvinyl chloride (PVC) and polyethylene teraphalate (PET) containers. The second class contains polypropylene (PP) and natural (primarily milk containers) high density polythylene (HDPE) containers. The third class contains opaque materials such as rigid, mixed color high density polythylene (HDPE) containers, opaque polyvinyl chloride (PVC) containers, opaque polystyrene (PS) containers, and opaque polypropylene (PP) containers. The groups of plastics contained in each of the classes are then separated out using the same or other detection means.