Firstly, people dont just consider War Nickels as such.. they "are"
war nickels and contain silver. 1942- 1945 are the war nickel years,
but "only" the nickels with a big Mint Mark above the Monticello on
the back. (P, D etc)
Correct me someone if Im wrong, but I think the only year with some of
both, is 1942, where some are silver and some are not. War nickels "will"
have the mintmark 100%.
Silver was used in the nickels because of the need for other metals during wartime.