Origins of soaps in ancient Egypt
“For soap Egyptian used natron, swabu (derived from swab meaning to clean), a paste containing ash or clay, which was often scented, and could be worked into a lather, or the like. The Ebers Medical Papyrus, dating from about 1500 BC, describes mixing animal and vegetable oils with alkaline salts. The soap-like material was used for treating skin diseases, as well as for Washing.”
*As noted from the Egypt Timeline article