In 18th century America, women stored leftover cooking fats all year in preparation for a yearly soapmaking day.
Solid fats were rendered, then boiled and strained to remove hair and dirt.
Lye was made from hardwood ashes collected from fireplaces.
Rainwater was leached through the ashes and a fresh egg determined the strength of the lye solution. If the egg floated, the lye was too strong, but if it sank slowly the lye was deemed to be the correct strength.
The lye and fats were then stirred together.
Soapmaking was an inexact science, resulting in a soap that may have been soft, hard or harsh.
Whatever the result, it had to suffice until soapmaking day the following year.
Some hundred years or more later, entrepreneurs visited households and bought fat from the households, then made soap and sold it back to the women in large blocks.
Soapmakers also often manufactured candles, as both candles and soap were both made with tallow.
William Colgate opened a soap factory in New York in 1806, but it wasn't until the 1830's that soaps were sold individually wrapped with a uniform weight.
Colgate introduced a perfumed soap, Cashmere Bouquet, in 1872.
William Procter and James Gamble, married two sisters and set up a business in Cincinnati, selling soaps and candles from a wheelbarrow until their business grew and became known as Procter and Gamble.
Another company known as the B.J. Johnson Company made soap from vegetable oils - palm and olive, and cocoa butter. Its soap became so popular, the company was renamed as Palmolive.
However, the Palmolive soap today differs vastly from the original Palmolive soap.
A Kansas business, the Peet Brothers merged with Palmolive to become Palmolive Peet, then with the Colgate Company in 1928 to become the Colgate Palmolive Peet Company before dropping the Peet from the title in 1953, forming the name Colgate Palmolive.