appearance aussie Australian banknotes cash color colored colors colour coloured colours currency decimal-currency finance historic history low-value monetary money notes numismatics obverse old outdated pre-decimal-currency replaced security superceded superseded textures value values reverse canada change coin coinage coins colorful decimal dollar dollars dough euro europe green note potential soiled used various denominations wealth cambodian Cambodian-riel denominations Khmer-currency KHR riel success variations variety various high-denominations fifties fifty