I think that I need to retract my advice on the finish. I was talking about more of a replacement of a finish, rather than cleaning up an existing finish. If a person didn't want to damage an original finish, with original markings, in order to maintain a historical value, then the approach that scorch recommended is preferable to what I suggested. However, if you did want a new finish, then my suggestions are unchanged.
For the sake of information, the original finish on the stock would most likely have been BLO or possibly Tung Oil.