I have written a number of reviews of the Andy Griffith Show, but this one is close to my heart, because it brought back memories of the products promoted to kids to sell, including salve and greeting cards.
Ads directed at enterprising kids were placed in the closing pages of popular magazines such as "Boys' Life". I know I tried (once) to sell greeting cards for a company in Elmira, New York. Of course my parents and closest relatives saved me by buying the minimum required.
The reaction of the "executive" at the Miracle Salve company upon hearing Barney and Gomer's routine as to how their salve cures mange on dogs is one of the best scenes of the show.
Overall, a great episode of the pure comedy type that many go to Andy Griffith for.