I've been using either a tumbler or vibratory machine, always with dry media since these machines became a fad about forty years ago. I've not had the dust problem that many here mention. If you're getting dust it may be because you're using a dry media not intended for brass cleaning or maybe the media is of poor quality. Put a tablespoon of mineral spirits or a commercial liquid polisher like Dillon and others sell. That should eliminate dust entirely.