Play-Doh started life as wallpaper cleaner.

In the early 1950s, a Cincinnati compound manufacturer named Noah McVicker was trying to solve a very unglamorous problem: coal-heated homes left a film of soot on wallpaper, and the standard rubber erasers of the day weren't cutting it. McVicker's solution was a soft, pliable, non-toxic paste that could be pressed against the paper, rolled off, and take the grime with it. It worked.

Then American homes switched to natural gas and electric heating. The soot problem vanished almost overnight, and McVicker's cleaning compound had no market left. His sister-in-law, a nursery school teacher named Kay Zufall, noticed the stuff was remarkably similar to the modeling clay her students used — only softer, cheaper, and easier for small hands to manipulate.

Zufall convinced McVicker to pitch it as a toy. In 1956, it landed on store shelves and in a new TV segment targeting children. The name 'Play-Doh' was Zufall's invention too. The original color was off-white; the iconic primary-color sets came later, once it was clear the toy was a hit.

By 1958, Play-Doh had generated over $3 million in sales. The compound itself barely changed from the wallpaper-cleaning formula — a wheat-based, non-toxic paste that smells, to this day, exactly the same as it did in a Cincinnati factory more than seventy years ago.