Clay was originally invented as a wallpaper cleaner
Play-Doh, which is used as modelling clay, was first invented as a wallpaper cleaner in the 1930s by a soap manufacturer. The product aimed to help remove the layer of soot from wallpaper, as coal was popularly used to heat homes during the period. Later, as the use of coal decreased, the clay was repurposed as a product for pre-schoolers.