I just got off the phone with Jim Woods at McSpadden. One of our dulcimer friends has an old McSpadden -- 1967 vintage; and was told by Lynn McSpadden not to put anything else on there. Well, 50 years later, that dulcimer is just a bit dusty and in need of refreshing!!
Jim told me that "back in the day" they used "furniture wax" -- carnuba wax, that is -- on those dulcimers. So if you've got an oldie McSpad that needs a facelife, hunt up some carnuba wax and get polishing!
updated by @ken-hulme: 10/27/19 12:02:25PM