During the early years of the Civil War, in response to the political uncertainty of the time, the banking industry suspended the redemption of paper money for coin. The net effect of this action was to place a premium on coins vis-a-vis paper money and there resulted a widespread hoarding of coin by the public. Coins of all denominations were jealously guarded and hoarded and soon had all but disappeared from circulation. This was partly alleviated by small denomination (less than $1) U.S. postage stamps. People would encase the stamps and use them for trade.
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