A boxtop, in the context of being a proof of purchase

Proof of purchase

Proof of purchase is often required for sales promotions and manufacturer rebates as evidence that the customer purchased the product. When multiple purchases are required to redeem these rewards, it is referred to as a premium incentive or collector mechanic.Traditional proof of purchase systems...

, is understood to be the upper portion of a product box, detached, and mailed as part of a claim for a radio premium

Radio premium

During the time that radio programs were the dominant medium in the United States, some programs advertised "souvenirs" of the various shows, which were sometimes called radio premiums...

 or other advertising offer. During the 1930s through 1950s, cereal boxtops were usually the most common proofs of purchase used to claim such premiums.

Popular cereal boxtops of the period were Wheaties, which sponsored Jack Armstrong, the All-American Boy

Jack Armstrong, the All-American Boy

Jack Armstrong, the All-American Boy was a radio adventure series which maintained its popularity from 1933 to 1951. The program originated at WBBM in Chicago on July 31, 1933, and was later carried on CBS, then NBC and finally ABC....

; Kellogg's Pep, which sponsored The Adventures of Superman

Superman

Superman is a fictional comic book superhero appearing in publications by DC Comics, widely considered to be an American cultural icon. Created by American writer Jerry Siegel and Canadian-born American artist Joe Shuster in 1932 while both were living in Cleveland, Ohio, and sold to Detective...

; Ralston-Purina, which sponsored Tom Mix

Tom Mix

Thomas Edwin "Tom" Mix was an American film actor and the star of many early Western movies. He made a reported 336 films between 1910 and 1935, all but nine of which were silent features...

 Ranston Straight Shooters; and various General Mills, particularly Cheerios and Kix, which sponsored The Lone Ranger

The Lone Ranger

The Lone Ranger is a fictional masked Texas Ranger who, with his Native American companion Tonto, fights injustice in the American Old West. The character has become an enduring icon of American culture....

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