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<p>[QUOTE=&quot;-jeffB, post: 4087033, member: 27832&quot;]Wow, that looks severely <i>corroded</i> on the cupronickel portions, and <i>mechanically</i> disturbed at the borders between the copper and cupronickel areas. I can&#039;t imagine how metal migration could&#039;ve led to that appearance -- but, as I said in another thread, I&#039;m not a metallurgist, so that&#039;s not at all surprising.</p><p><br /></p><p><i>Very</i> cool example! I like coins that make me wonder...</p><p><br /></p><p>Edit: I wondered if the &quot;corrosion&quot; could be from <i>galvanic</i> attack on the nickel in contact with the exposed copper. But if that happened, it would happen <i>all the time</i> on clad coins, which <i>all</i> have copper exposed around their edge.</p><p><br /></p><p>Edit 2: To clarify, I don&#039;t know how metal migration would produce this result, but I have no alternative explanation, so, &quot;sounds good to me&quot;...[/QUOTE]</p><p><br /></p>

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