If you want to clean the grit and grime off, I would recommend Murphy's and warm water mixture. If you want to polish them, I would recommend paste wax. Either Minwax or Johnson & Johnson can be find at any hardware store. Rub it in like you would on a vehicle, let it dry for about 20 minutes then come back and buff it off with a nice clean, soft towel. You'll get a protective shine that way. This also works very good on blued steel and does not have the abrasives that most polishes have. Repels moisture too!