Coal heating left black soot on home walls. Kutol, a soap company, sold a soft putty to clean it: rolled over wallpaper, it lifted the soot.
Oil and gas furnaces later replaced coal, leaving less soot, and sales collapsed.
Nursery school teacher Kay Zufall, related to Kutol's Joseph McVicker, let her students shape it. They loved it, so she urged selling it as a toy. Reworked, it became Play-Doh, a children's modelling dough, in 1956.