If you looked in the kitchen cupboard of any middle-class home that had children living there circa 1965, you would probably have spotted former jelly jars now serving as glasses festooned with images of the Flintstones.
Welch's began the tradition of packaging jelly in commemorative jars that were designed to be used as drinking glasses in 1953. Its first subject was Howdy Doody. It was such a success that new series were released every couple of years. Others who were honored included Davy Crockett, the aforementioned Flintstones (three different series released in the early 60's), the Archies, Bugs Bunny and other Warner Brothers characters, football teams, Tom and Jerry, Dr. Seuss, and many others.
Welch's released a set of glasses as recently as 2002, so this tradition we grew up with is still going on.
In my house, we had some other sort of jelly glasses that were generic in nature. I believe it may have been a local brand. You could always spot a former container of jelly from the slightly protruding rim which provided a place for the lid to provide a seal.
It was simply good business for the makers of jams and jellies to provide motivation for consumers to buy their products. Jelly glasses were also a very user-friendly form of recycling. And among our social circle, such glassware would never be looked down upon, as everyone's cupboard was full of them.
Today, that original Howdy Doody series of glasses are collectibles, but affordable ones. As I wrote this piece, you could buy one on eBay for $25.00.
Nowadays, most jellies are sold in plastic squeeze bottle. They make really lousy glasses.