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10. Wooden bills

Wooden bills may have been rough on the wallet, but they were one of the ingenious ways that Germans devised to rebuild their economy following World War I. When the war settlement left the German economy in shambles, local townships took to printing "notgeld" (or "emergency money") on everything from wood and aluminum foil to silk linens and playing cards as a local form of payment until the Reichsbank recovered.

"What they realized was that collectors would buy up really odd money for collections, which essentially took it out of circulation and returned hard currency in its place," says Doty. His collection also includes a coin stamped on anthracite coal, a rarity now.

By CreditCards.com