After WWII steps were taken by the Allied Authorities to stabilize the continental Europe financial system.   One action was to disallow the use of the currencies of the occupying powers.   Thus when GIs arrived to their duty station it was required that they turn in their native currency and accept in its place specially printed money called "script".  

The intent was that this "script" could be used by the GIs to make purchases at PXs or other military commercial locations, but not be used in the local economy.  Script could be exchanged on base for Deutsch Marks for making off-base purchases.  In reality, local stubes and other commercial institutions would accept "script" with the objective of having cooperative GIs make purchases on their behalf at the Post Exchange at bargain prices.

To defeat such black market activity, periodically the miliary athorities would change the color of script making the previously existing paper money worthless. GIs were allowed to exchange their "old" script for the "new".   Such financial changes were initiated with great secrecy to avoid the ability of individuals "in the know" from buying up script from the native Germans for pennies on the dollar and making a substantial financial windfall.
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