Starting in 1959, the packaging for the uncirculated coin sets offered by the United States Mint was modernized. Rather than placing the coins in cardboard and paper holders, each coin was sealed within a cellophane compartment of a plastic soft pack, and placed within a paper envelope. This represented a better long term storage option for the coins and allowed for the sets to be produced in greater numbers. As opposed to the sets of the previous era, each set contained only one example of each coin issued for circulation from each mint.
The lower pricing point and standardized packaging led to the increased popularity of the product, which saw the number of sets ordered grow during this period. It started to become more customary for collectors to order one uncirculated mint set and one proof set for each year to keep their collections up to date. This would culminated with more than one million sets ordered in 1964.
The typical mint sets were not issued during the years from 1965 to 1967, instead special mints sets were offered. Regular production resumed in 1968.
A number of changes to circulating coinage occurred during this time period. In 1959, the reverse design of the Lincoln Cent was changed from the original depiction of wheat ears to a depiction of the Lincoln Memorial. In 1964, the Kennedy Half Dollar would be introduced, replacing the Franklin Half Dollar, after its abbreviated run. Starting in 1965, the composition of the dime and quarter were changed from silver to copper nickel clad and the silver content of the half dollar was reduced.