It'd be cool to see some follow-up pictures once you get the Verdi-Care and have conserved the coin. I'd look forward to seeing them for sure.
One suggestion Dave would be to go get distilled water and rinse it in that. Tap water has chlorine in it, and it can attack the copper. While using tap water for a rinse is "ok", always make sure you rinse it clean with distilled water. I know its a little late for MN, but you can use the water from a dehumidifier or your central air as well. My dehumidifier for years provided me the water to soak ancient coins in when I used to clean them. Chris
That is a very good find. I have been wanting to get my machine out, but the ground is like concrete around here right now. Congrats on the great find.