No, I just did a couple of acetone soaks until all the green was gone, then distilled water rinse. no harm to the toning.
The 1939 Oregon Trail half dollar was the final one in the series. Only 3,000 from the Philly, Denver and San Francisco mints were issued.
Here is my Albany. It's graded MS 67+. Thankfully the fingerprint on the obverse is not too noticeable in hand.
I dunno why, but the Maine is one of my favorites. you gotta love the fake Maine's. I see them all over ebay, or at least ones that don't look real. Where did you get yours, @dwhiz ?