[lugerholsterrepair]

GT, My guess would be yes. It is neither hazardous nor is it explosive, flammable or corrosive. I can't see why the PO would have any reason to forbid it. In my small local PO they do not even ask about what might be in a package. Of course there are the usual posters showing what cannot be shipped but empty brass would fall into the catagory of something like brass washers. They are inert. Jerry Burney