Zimbabwe will slash 10 zeros from its currency from Aug. 1, in bid to bring hyperinflation under control. Atleast that is the official line. Of course, redenomination can also be used as a method of confiscation. The Zimbabwean government may demand that such an exchange takes place within a short period of time, hoping that not all Zimbabweans will exchange the available cash. The old currency that won't be exchanged is essentially revenue - indirect seignorage - for the government.