That changed towards the end of 1963 when President John F. Kennedy was assassinated, the US got involved in Vietnam and other innocence was lost. It was also a time that led to a big change in the country’s legal tender; the US Mint stopped minting silver coins out of 90 percent silver and anyone who stumbles across a quarter, silver dollar, dime or half-dollar minted prior to that date should pocket that pre 1965 silver coins.
Current legal tender is now minted of an assortment of less expensive metals than silver (silver prices have currently ranges from approximately $31 to $35 per 1 oz silver). The reason for the change away from using precious metals was that the silver weight value of the coins started to outweigh the proclaimed face value of the currency. That resulted in numismatists pulling those coins out of currency by the poundful. While there are not of ton of pre 1965 silver coins remaining in circulation, is one should appear in your spare change, pull it out and put it aside as it is worth something more than face value.
Ever since that change to currency, pre 1965 silver coins have become the bar of comparison. Now contemporary silver coins are a sandwich coins made of copper and silver. That is why if you are lucky enough to end up with an pre 1965 silver coins, saving that spare change may result in a profit.