I've got a bunch of .44 magnum I've been saving. Got the gear to start reloading and started tumbling my brass. I guess some of it got shot in the rain or snow because it's kind of tarnished. Looks like carbon. I have tumbled it for hours using walnut shell media. This cleaned it up a bunch but not entirely. When I scratched at it with a knife you could see clean brass underneath. It is also totally smooth on the outside where the discolorations are.

It looks safe to use but thought I would ask the hive. None of my friends reload.I tried to take pics but the stuff doesnt show up in a photo. Thanks

won't hurt it. I load tarnished 9mm brass al the time. Just make sure it is tarnish and not corroded. If it bothers you just use a real fine steel wool and touch it up.

It'll reload just fine.  If you want to remove any oxidation, soak the brass in a solution of Lemishine.  Do a search and you'll find several threads on the subject.  You can pick Lemishine up at a grocery store in the dish detergent isle.

gpt photos OP