when did nickels stop being made of nickel
Nickel (United States coin) With the entry of the United States into World War II, nickel became a critical war material, and the Mint sought to reduce its use of the metal. On March 27, 1942, Congress authorized a nickel made of 50% copper and 50% silver, but gave the Mint the authority to vary the proportions, or add other metals, in the public interest. The Mint's greatest concern was in finding an alloy that would use no nickel, but still satisfy counterfeit detectors in vending machines. An alloy of 56% copper, 35% silver and 9% manganese proved suitable, and this alloy began to be coined into nickels from October 1942. In the hope of making them easy to sort out and withdraw after the war, the Mint struck all "war nickels" with a large mint mark appearing above Monticello. The mint mark P for Philadelphia was the first time that mint's mark had appeared on a US coin.[91] The prewar composition returned in 1946; all nickels struck since then have been in 75% copper and 25% nickel.[92]