Play-Doh modeling compound started out as wallpaper cleaner. Joe McVicker learned from a teacher that kids usually found modeling clay too hard to manipulate. Discovering that the squishy cleaning product he manufactured could substitute, McVicker shipped some to the school. After teachers and kids raved, he offered to supply the product to all Cincinnati schools. More rave reviews followed. McVicker showcased the modeling clay at a national education convention in 1955, and word spread to Macy’s and Marshall Field’s. By 1956, the wallpaper cleaner had become Play-Doh.

Source: National Museum of Play