This is a test procedure for detecting contaminants or a method for removing contaminants from toner to be used in an electrophotographic marking system. The method simulates the mixing and separation of contaminants that occur in an actual development system. It has been determined that contaminants in toner have tribo properties that prevent strong adherence of these contaminants to the carrier whereas purified toner has tribo properties that permit stronger adherence to the carrier. A separation procedure and method is thereby used to remove or identify contaminants.