Cut the loop off a Glock bore brush rod. Chuck in a cordless drill, smear Fritz on the brush, and run it in and out the chamber like you were honing it. Also works good polishing reloading die bores. It'll get it mirror. If a person doesn't have Fritz. Aluminum mag wheel polish, Meguiar's polishing compound etc. Rinse the polish out the chamber/bore with some mineral spirits. Works like a charm.