Everybody knows how much of an absolute hassle cleaning coal residue off wallpaper is. Wait, I wrote that wrong. Nobody remembers how much of an absolute hassle cleaning coal residue off wallpaper was since nobody uses coal-burning stoves for heat anymore. Actually, come to to think of it, I don't think anybody really uses wallpaper anymore either.
Anyway, back in the early to mid 20th Century, before washable vinyl wallpaper was invented, it was very difficult to clean coal residue off walls. To help their customers with this problem, Krogers Grocery had Noah McVicker of Kutol Products develop a putty compound which consumers could use to "pick up" the coal residue off their walls.
A can of Kutol's Wall Cleaner
After World War II, American homes started switching to natural gas heating and vinyl wallpapers, so the demand for Kutol Products' compound started to drop dramatically. On the verge of bankrupcy, the company hired McVicker's nephew Joe, in an attempt to save the company. After hearing that the wallpaper cleaner was being used in nursery schools to make Christmas ornaments, Joe was struck with an idea that would change the world forever.
In 1956 Joe formed the Rainbow Crafts Company and began advertising his uncle's cleaning compound as a modeling compund for children. He renamed the product "Play-Doh." The product caught on in America after Macy's and Marshall Field's started stocking the item in their stores. since that time nearly 2 billion cans of Play-Doh have been sold.