I've always done it per Roy Dunlap's instructions in his old book "Gunsmithing".
You make a lap out of a case fired in the gun by attaching a rod through the primer hole, load the lap with rouge (Very fine polishing compound) and slowly turn the lap in the chamber with a hand drill until the chamber is polished acceptably. He did it with a hand-powered drill, but I always use an electric variable speed on very low RPM. I use a bit of light oil to lubricate the lap.
I don't think 0000 steel wool would do much - No abrasive in it. Might burnish it some if you used some elbow grease I guess.
I recon 'ol Roy "Dun lapped" a few chambers in his time and knew what he was talking about. Usually works good for me (Unless the chamber is really bad)...