Five actors in "The Jar" appeared in various roles on The Andy Griffith Show (1960): George Lindsey (86 of its 249 episodes as Goober), James Best (2 episodes), and Alice Backes, Sam Reese, and Carl Benton Reid (1 episode apiece).
Final TV performance by Jane Darwell, appearing several months before her very last movie performance in Mary Poppins (1964) as The Bird Woman.
Charlie gifts his wife a hair ribbon with her name stitched on it which had cost him 65 cents, at a nickel a letter. Her name, Thedy Sue Hill, is only 12 letters, so it would seem he was overcharged by a nickel. The extra nickel was likely the cost of the ribbon itself.
The tune playing while Charlie shows Thedy the jar is similar to the music played during the opening credits of The Shining (1980).