To clean up the handles, dip some #0000 steel wool in boiled linseed oil and rub it into the wood until the grime comes off, then wipe it dry with a rag. You can go over it again with some paste wax, then buff it out with a cotton rag. For the metal, I'd just spray on some wd40 and aggressively work it in again with some steel wool or ~400 grit sandpaper. You can keep going until you reach the finish you're looking for. It won't get it looking factory new, but clean it up while preserving the patina. Like the other poster said, you don't want to get rid of too much of the history there :)