[Unclenick]

They're fine. If you have to store exposed lead for a long time, rub a little Johnson's Paste Wax on it to prevent that.

The oxide layer is harder than plain lead. I would not shoot lead bullets, airgun pellets, or un-patched round ball or miniball with that coating. It is abrasive to the bore if it makes contact with it. It also doesn't shoot as accurately as normal. Don't ask how I know.