When did the US move the mint marks back to the right of Montecello on nickels?

Question: I read the article about Mr. Frith finding a rare Jefferson Nickel with a new 1942 die for the front of the coin but the back had the old 1941 die with the mint mark to the right of Monticello. I have two nickels, one 1947 with a S mint mark and one 1949 with a D mint mark both to the right of Monticello like they used to be pre-war. Either I have two very rare coins or the US moved the mint mark back to the side of Monticello and made it smaller again at some point after 1942. Can you tell me if they moved the mint mark back to the right side of Monticello after 1942?

Thanks for your time.
Susan Burke

My Answer: Yes, the mint mark was moved back to the right of Monticello in 1946 on Jefferson Nickels. It was only during the war years of 1942-1945 the it appeared above the dome of Monticello. These "wartime" nickels were issued from October 1942 through December 1945. This was only to make it easier to determine that these coins were made of a different composition.

During World War II, nickel was a critical war material, so nickels dated 1942-1945 were made without nickel. They were comprised of 56% copper, 35% silver and 9% manganese.

Beginning in 1968 the mint mark was moved to the obverse or front on the Jefferson Nickel.