If your brass contains lead styphnate primers, you don't want to operate a dry tumbler anywhere in occupied space or where the dust containing lead salts will contaminate surfaces that people touch. Fresh media slightly dampened with a liquid polish additive will generate less dust, but the dry tumblers have a poor seal and after some use they will be sifting dust all over everything nearby. The best place to use them is outdoors or in a dedicated shed that can be hosed down.
