On old guns with an unknown finish I use a cotton rag with mineral spirits(oderless paint thinner) to disolve and wipe away old grime. It won't dissolve the finish but will remove old wax, oil, dirt, ect. Some gentle rubbing and several old rags should clean it without altering the original finish or color.. Problem with many modern furniture polish/"cleaners" are they have silicone of some sort and/or mineral oil in them. Those can get under an old finish and cause it to lift. Once that stuff is in the wood you can't get it out. Renaissance Wax is great stuff. I usually buff on a couple coats of Johnson's or Butchers past wax if it needs it. Good luck.
