Which packaging innovation was initially rejected by consumers as 'unnatural' but later became ubiquitous after a marketing campaign featuring children demonstrating how to use it?

Product packaging has evolved dramatically over centuries, with certain innovations revolutionizing entire industries and consumer behaviors. Some packaging inventions solved major problems, extended product shelf life, or created entirely new market categories. This trivia question focuses on a packaging breakthrough that transformed how we consume everyday products and led to significant changes in retail, manufacturing, and consumer habits.

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The pop-top aluminum can (1963)
The squeezable plastic ketchup bottle (1983)
The resealable zip-lock plastic bag (1954)
The flip-top squeeze cap for Heinz ketchup (2002)