1964 (and before) Nickels?

The U.S. 5 cent coin is made of .750 copper and .250 nickel 1865-1942 and 1946 to the present. On Oct 8 1942 due to World War II the composition was changed to 56% copper, 35% silver and 9% manganese. All the silver nickels of this time had a very large mint mark over the dome of Monticello. It was the first time a P mint mark was used for the Philadelphia mint. Do not for get that the 1/2 dollars from 1965-1970 are made of 40% silver and are still out there. I ask for 1/2 dollars at banks and when they have them, I find a few of the 40% 1/2 dollars in the rolls.