Magnetic pulley are positioned at the head of belt conveyors to extract metal contamination from the product on the belt. As the roller rotates, it holds the tramp metal while clean product is discharged. Finally as the belt leaves the roller, the magnetism dissipates, and the unwanted contamination falls from under the belt into a separate receptacle. This type of magnet acts as secondary protection for deeply embedded metal in the product, which may have not been initially extracted by an overhead suspension magnet.