Here there's usually a core charge on drum shoes even when buying new shoes. Likely to provide cores back to the manufacturing companies for the lower priced remanufactured lines of shoes that don't use new steel. I can't remember ever buying a set of brake shoes that didn't require a core here. Disc brake pads just get discarded. I'm sure some communities would collect them as part of "hazardous waste" considering old linings might contain asbestos. I've never had that issues as I've always turned them in as cores to be rebuilt for someone else.
Luke P-3C and P-8A Maritime Weapons and Tactics Instructor, Instructor Tactical Coordinator and Mission Commander
See if the local salvage/junk yard will take them. Steel is steel. The scrap I see being loaded on trucks is composed of just about everything on a vehicle except glass, rubber and plastic which can't be loaded with a magnet.