a screening system designed to provide separation of multiple fractions of new screens fines . news screens fines contain a mix of compressed , unmarketable recyclables that are generally less than four inches in size created as a by - product of current material recovery facility plant designs used to process single - stream recyclables . the nsf separation system uses a series of primary and secondary classification apparatus to separate materials into marketable products that meet legislative requirements . a series of screens , conveyors and air moving systems are designed to separate waste from fractions of glass , plastic and ferrous metals that can be sold .