These would clean up with a rotary, brass, wire, brush. Evaporust would work too. Soak in a medicine bottle or appropriate sized jar. It can be used over, if you filter out the rust particles. Joe will be able to speak on the use of Evaporust better than I can. I would clean them up just for the saving of them, but you may have many alike and not interested in having yet more. I have some somewhere in the biomass of my sewing room, yet to be discovered.