I once found a brazilian mil crucieros note in my garage (WTF was it doing in my garage?!). I held onto it in my wallet for a while. Later, on a trip to Dallas, I went to Heritage Galleries to see if James Halperin, (proprietor of HG and author of The Truth Machine, a book I'd recently read) to maybe get an autopgrah or something. He wasn't there, but I talked to one of the sales associates, who was an expert on numismology and currency in general. I pulled out the note to inquire about its worth. Turns out what I thought might at least be worth a few bucks (it was paper and 1,000 crucieros, whatever they are) was really, at most, maybe worth 1/100th of a penny.