As part of the continuing research to develop technology for conserving domestic mineral resources, the Bureau of Mines is investigating scrap identification techniques to improve sorted mixed scrap grade. This paper focuses on various classes of wrought and cast copper alloys produced with recycled scrap. Based on a survey of the literature, principal alloys, such as the brasses and bronzes, are examined with respect to impurity elements and their effects on metallurgical behavior. Effects of various elements, including lead, antimony, iron, chromium, and aluminum are discussed. The metallurgical effects described include hot shortness, fire cracking, and undesirable phase transformations.