This compound of flour, water, salt, boric acid, and silicone oil was originally manufactured as a cleaning substance for wallpaper. (The dough-like cleaner was rolled against wallpaper to remove built-up soot.) In 1955 it made the shift from household product to plaything after its inventor, Joseph McVicker, heard a teacher he knew mention how difficult to work with her students found the clay then used in classrooms, according to Snopes.com.
A supply of the wallpaper cleaner was provided to her, and the kids she taught loved it. Seeing that, the entrepreneur supplied schools in the Cincinnati area with the substance, getting his “play dough” into the hands of thousands of product testers.
News of the product spread, assisted in no small part by McVicker who demonstrated and sold the item in the toy department of Woodward & Lothrop Department Store in Washington, D.C. Grasping the toy’s potential, McVicker formed Rainbow Crafts to manufacture Play-Doh. He subsequently sold that company and all rights to Play-Doh to General Mills. Joseph McVicker became a millionaire before the age of 30, and an immensely popular playstuff came to be internationally marketed and vended. These days Play-Doh belongs to Hasbro.