This is why the US issued special currency in Hawaii and North Africa during the 1930s. They were afraid of an invasion and by the currency being different the Treasury could simply cancel the entire series.
An interesting bit of history.
Thanks.
Faced with a $200 million stockpile of US currency, military officials opted to destroy all the recalled currency instead of overcoming the logistical problems of shipping the currency back to the mainland.[3][4][5][6] At first, a local crematorium[a] was pressed into service to burn the notes. To ensure complete destruction, a fine mesh was placed on the top of the smokestacks to catch and recirculate unburnt scraps of currency escaping the fire.[3]
Progress on the destruction was slow, and pressed with time, the bigger furnaces of the Aiea sugar mill were requisitioned to help burn the currency
https://en.wikipedia.org/wiki/Hawaii_overprint_note