1 Answer

You can not exchange it as it no longer holds value as money. These notes are now collector notes. You can sell it to a collector or at an auction. 

"Hyperinflationary Zimbabwean banknotes (such as the $100 trillion denomination) have gained considerable interest from the Numismatic community and buyers in general for its absurdity rather than the design. Some examples of such notes may be sold further in excess of their true face value.^[52]

The price and value of a Zimbabwean banknote depend on various factors: the rarity, based on factors such as the name of capital city, how long it was printed, or the type of watermark; its condition, and the national situation at time of issue, such as shortages or hyperinflation.^[53] Common designs and variants such as the $100 note of 1995 (Pick no. 9) are usually valued at about $1 apiece, while rare varieties such as the $10 Salisbury error note (Pick no. 3b) and the Standard Chartered issues are valued at around $100 or more. Zimbabwean banknotes are usually sold by banknote dealers over the counter or on the internet, although the most valued types theoretically qualify for inclusion in auction." 

http://en.wikipedia.org/wiki/Banknotes_of_Zimbabwe