Inventions
Play-Doh was sold as a wallpaper cleaner for more than 20 years before it became a toy.
The putty was made in Cincinnati from the 1930s to wipe coal soot off wallpaper. When cleaner heating systems killed the market, a nursery school teacher noticed children loved modelling with it.
Why is this true?
The company removed the detergent, added colours and a scent, and relaunched it as a toy in 1956. More than three billion cans have been sold since.
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More about inventions
Most inventions arrive by accident, in the wrong order, or decades before anyone finds a use for them. Microwaves, sticky notes, safety glass and vulcanised rubber all started as mistakes or side effects. The facts here trace how the thing actually came about, note who noticed the accident and why it mattered, and point at a source so you can follow the full story if it hooks you.