As Dan noted, this is my understanding as well. Many were so badly "rubbed" that some barrels were rubbed/worn almost though to the bore. Some militaries issued bone or other materials for "rubbing" the barrels and furniture, but some or perhaps most soldiers used their steel ram rods as no other material would get them bright enough for some commanders.
Noted in Firearms of the American West, oft times, T-guards, butt plates etc, were bent from polishing off the muskets and were sent to the armorer because they no longer fit.