Abstract: A roller is described for applying lacquer and the like to metal sheets to be formed into metal containers. Roller comprises a magnetic cylindrical former and a cover magnetically retained on its curved outer surface. Cover has an outer layer made from a castable material which is selected from the group comprising liquid polymeric systems and liquid prepolymeric systems capable of forming macromolecular structures having elastomeric properties, and an inner layer made from a castable material which is selected from said group, which is capable of bonding with the outer layer and which has particles of iron powder dispersed therein. A method of manufacturing the cover by a centrifugal casting operation is described.