Soap is made largely from fats or oil, with a variety of other ingredients.
Before the introduction of soap in the 1st Century A.D. people ‘washed’ themselves and their clothes with fuller’s earth, a fine clay-like substance that loosens oil and dirt.
People first made their own soap by saving scraps of fat and boiling them in an iron pot. They added an alkaline solution, made from wood ash, called lye. This formed a yellow coming from the potash in the lye. Hard soap was made by boiling for longer, and by adding salt, usually from sea-water.
Soap is still made in much the same way, but on a far larger scale in modern factories. The chief things that go into its manufacture are still fat or oil (but oil from coconuts or cotton seed), lye containing postah, or sodium, and salt. Colored dyes, perfumes and super-fats such as almond oil and glycerin, are added to make the expensive toilet and shaving soaps.