Non ferrous metals are reactive to magnets, just not predictably. For instance if you drop a rare earth magnet into a thick copper tube, the magnet slowly glides to the bottom of the tube. Some scrap yards use rotating magnets to sort nonferrous metals from trash by placing them at the end of a conveyor. The plastic, foam, wire casings, etc fall normally off of the conveyor, but the nonferrous metals catch a ride on the rotating mangetic fields and are tossed up and over to a seconday chute. Food for thought.