Oh my.. This one and the 17-D have been my favorite in the entire Lincoln set on CoinFacts. It's one the reasons I fell in love with BN Lincolns. 67BN... wow. It's price jumped to 10k
GDJMSP warns about using acetone on copper, although I don't believe him 100% on this. I can't see anything acetone would do for this, and I don't see any verdigris that VerdiCare would help. I would use hot running water, a distilled water rinse, and then the VerdiCare if you wish...Thad can use the business : - )
From the Verdi-Care FAQ: "It is recommended to rinse or soak the coin with distilled water followed by acetone to prepare the surfaces. With copper, a quick soak in xylene may be helpful as well. These steps are not required, but are recommended and will result in the best application."
That holder is a Whitman. Whitman holders have 3/16" aluminum screws and their Logo, a W inside a circle hot stamped on the edge.
My one and only matte proof. Not a high grade, but the color makes up for it, I say. Crossed from NGC to PCGS - PR62RB in both cases.