Found this article by Kate Springer on CNN.com:
Secret treasure: Historic banknote found inside ancient Chinese sculpture
At the risk of giving away too much from the article (you should read it!), this is a photograph presented in the above link showing both the sculpture and the banknote found inside it:
The banknote is 700 years old and, naturally, a rarity. Makes one wonder how it got there (did the owner of the sculpture hide it there with the intention of using it later? What happened then? Did he/she simply forget it was there? Did they pass away before telling anyone it was there? Did they sell/give away the sculpture and forgot they had cash stored within? The possibilities are, I suppose, endless)
Fascinating, fascinating stuff.
This was also in the article and provides yet another fascinating look at how things rolled back then:
The (discovered) bill is endorsed by the emperor himself, with three official red seals and a line that reads: “Authorized by the Department of Finance, this bank note has the same function of coins. Those who use counterfeit banknotes will be beheaded, the whistle-blower will be rewarded 250 Liang silvers plus all the properties of the criminal. The third year of Hong Wu period.”
Yikes!
They took counterfeiting very seriously back then!