CU-1C-1986-15 Cud

Description

Preservation of zinc-era cud coins demands particular attention to storage conditions, and CU-1C-1986-15 on the 1986 Philadelphia Lincoln Memorial cent is as vulnerable to environmental deterioration as any post-1982 cent. The copper-plated zinc composition creates a galvanic couple at any point where the thin copper plating is compromised — and the exposed zinc core within the cud area is one such point. When moisture reaches unplated zinc, it initiates an oxidation reaction that produces white zinc oxide and, in more advanced stages, zinc hydroxide and zinc carbonate compounds. These corrosion products can spread beneath the copper plating adjacent to the cud, lifting and blistering the plating in a progressive failure pattern colloquially known as "zinc rot." Cud specimens are particularly susceptible because the cud surface itself is unplated zinc that was never intended to be the coin's outer surface. Collectors should store zinc-era cuds in airtight holders with desiccant, avoid handling without gloves, and inspect specimens periodically for early signs of white spotting that could indicate incipient corrosion. CU-1C-1986-15 is the fifteenth cataloged die break for this date from the Philadelphia Mint. Struck on copper-plated zinc planchets (97.5% zinc, 2.5% copper) at 2.5 grams and 19mm.

Attribution History

• Discovered by David Curfman
• CU-1C-1986-15
• Expert attribution by Cuds on Coins

External References