My most unusual find was some time ago around 1976. Iwas buying banknotes from local people, after advertising in the newspapers, and on one such ocassion I bought a wallet that had several notes in it.
I paid a fair price for what was contained therein and went on my way. I was doing a lot of buying in those days.
It was a couple of months later that I was going through the notes that I had bought, to house and catalogue them properly, I noticed a flap in the billfold container part of the wallet. I opened it up and much to my surprise I found a 1954 Devils Head asterisk note, now known as BC-31aA.
I couldn't remember who I bought it from but in the over all picture it didn't make a lot of difference because a year later I was displaying notes for Canada Coin week at a Mall Show and during the show it vanished.
Live and learn.