Corrosion On Zinc Coins

You might stumble upon a collector who loves extreme examples of (unruptured) Zincoln gas bubbles.

This is a video from the government about making pennies a long time ago. They wash them in vats with Cream of Tartar (a baking agent similar to baking soda). I think it would work on new pennies since it is a topical wash.

(Please note: I have not tested this method)

https://www.youtube.com/watch?v=egZ6WfXm08w

The only way to get coins that are unaffected by bag marks is buy business strike quality specimen coins that are specifically made for collectors.

As coins for circulation are ejected from the coining presses, they fall onto a pile of already freshly minted coins, and also get marked up when they are transported in bulk. This is where so called 'bag marks' come from.
With Zincolns, the copper plating is damaged, and so sets the scene for zinc rot.

Rolls and bags of uncirculated coins fresh from the Mint have bag marks as mentioned above, and so grade in the MS-60 to 65 range.

Specimen coins from mint sets are usually grade in the MS-65 to 70 range, and most commonly 68 to 70.
However, although more can may be taken in the minting and packaging of specimen coins,
I doubt that any extra care is taken for Zincolns during the rolling blanking and planchet stages, and so the possibility of zinc rot remains under the copper plating.

As we all know, zinc rot destroys the numismatic value if it is present. That may be a problem for mint sets over the long term. I don't know if the Mint takes any extra care for proof Zincolns during the rolling blanking and planchet stages of manufacture.

Perhaps the Mint should make silver proof Lincolns for collectors. I can see a marketing opportunity for the Mint in this respect, and there would be no zinc rot.

Look, my opinion, I have zincolns going on 31 years kept in flips and mostly undisturbed that have serious split plating issues. As long as they aren't seeing circulation, i.e finger rub and oils, moisture, ect. the exposed zinc dusts over and it stops and that's it, it's the repeated knocking off of this zinc dust that deteriorates the coin rapidly in circulation from water, hands, pockets, other coins ect.

31 year old, plenty of exposed zinc, just about every device has split plating. This one saw some circulation I'm guessing but I found it early, No idea why the front looks the way it does except for circulation I suppose? Not a filled die although the L in Liberty is missing, the entire obverse is pretty weak but it's got the strange abrasions Left, jacket, face... anyways, I just saved it as an example of split plating on the reverse as a reference:



if zinc is exposed, it's going to create zinc oxide to protect the exposed zinc. If you handle it, the oxide keeps getting knocked off and some more zinc is sacrificed to protect the exposed zinc. Blisters or bubbles if they aren't ruptured are fine, but they are ugly in my opinion.

Would it be evil to treat zinc coins and Zincolns with a little bit of WD-40 to stop corrosion?

Truth!