Message:

<p>[QUOTE=&quot;lehmansterms, post: 2819135, member: 80804&quot;]US coins are not my <i>metier,</i> I&#039;m an ancients guy, but I believe that I was told by one of my more US-obsessed friends that the &quot;Zincolns&quot; (great name for them, I never heard it before) in addition to their microscopically thin (I&#039;ve heard &quot;1 molecule thick&quot; but suppose that&#039;s an exaggeration) plating of copper, have a thin coating of a very tough, clear plastic polymer (something like an epoxy) as their outermost surface. It is this virtually invisible layer which actually seals the coin and keeps the zinc from oxidizing. It is very tough - tough enough to protect a lightweight coin like a zinc cent in average contact with other coins in a cash-drawer or pocket. Drop that same cent on the sidewalk cement or parking lot asphalt and step on it - or subject it to anything else that could interrupt the plastic glaze - the voids, even microscopic voids, in the plastic coating can be a source/locus of a future corroded spot or area. Anything that will introduce microscopic holes in the polymer coating can then allow the elements through. Oxygen can reach and affect the stability of the zinc core and will begin the destructive processes which proceed so quickly on zinc surfaces.[/QUOTE]</p><p><br /></p>

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