When was silver taken out of nickels?

The term Silver War Nickels refers to those produced by the United States Mint from mid-1942 to 1945. These nickels differ from those minted before and after World War II, as those were made from 56% copper, 35% Silver and 9% manganese.

In WWII, The United States had to use 56% Copper, 35% Silver, and 9% Manganese. The dates for these 35% silver nickels are 1942(P,S) (NOT D), 1943(P,D,S), 1944(P,D,S), and 1945(P,D,S). The mint marks on these coins are located above the dome of Monticello.

Contrary to popular misunderstanding, these are the only US nickels that ever contained silver. The rest are all made of an alloy of 25% nickel and 75% copper.