Australia’s currency is the 5th most traded in the world (behind the US dollar, the Euro, the yen and the pound sterling). My brother brought back some Australian bank notes from his stay there. Hey, what’s that? I want it! I said when he opened his wallet, and promptly traded with him for South African rand. The surprising thing to me was that all the notes are in polymer, and have been like that for a long time, since about 1992. There were issues initially with colors fading and ink coming off, but those have all been resolved. The polymer bank notes last longer (than paper), are much harder to tear, more resistant to folding and soiling and are waterproof (and also washing machine proof). They are easy to process with teller machines or vending machines, and at the end of their life can be shredded and recycled. (Not bad. But even with all that, I wonder if Americans will ever bite and take to polymer money. We still refuse to let go of the paper dollar bill and make it into a coin).