For shotguns, rods were often hardwood, with brass joint fittings. Metal rods were more expensive. My Grandfathers 12ga shotgun kit is like that, and includes a steel brush, which is not long like today's brushes, its kind of a flat disc with curved "arms" forming a bore size circle. A large loop eye for patches and a "mop" swab that is slightly over bore size. This kit was for his 1909 Ithaca, and I doubt was much changed from kits 30 or 40 years earlier.
As noted, special solvents were not needed black powder, hot water being enough to do the job, with oil after drying for rust prevention.