Yes BuffaloBoy is right. You always want to keep your pure nickel nickels because they are worth about 2x face value because they are pure nickel. The years for pure nickel nickels are 1922(when they were first minted)-1942, 1946-50(some 1951 commemoratives), and then 1955-1981. Some of the nickels in 1942 and the 1943 nickels were made from tobac because nickel was needed for WW2 and then 1944, 1945, most 1951s the 1952, 1953, 1954 were made from chrome plated steel because again, nickel was needed for war those years. 1982 was the first year of a copper-nickel composition just like your american nickels and this was phased out in 2000, 2001 when the composition was switched to mainly steel. Any coins bearing either king george V (1910-1936) or king george VI (1936-1952), or with the young queen elizabeth (these were minted from 1953-1964) all have more numismatic value than bullion value.
Don't expect to get more than face value for 1982-now nickels.