] My mum was saying today that her grandmother's contemporaries (she was born c 1873) used washing soda for just about everything, including washing hair and face. Clearly you wouldn't use a strong solution, or you'd burn yourself badly. But great granny had wonderful hair and a fabulous complexion by all accounts, despite terrible poverty. I don't know if washing soda was available in JA's day, but I suspect something similar would have been.

I've made a research on Great Wash in JA times once, so I'm able to offer a few suggestions for available means of washing. Soda, i.e. sodium carbonate, wasn't very often met in JA's times, and then only in (costly) glass production or Marceille soap (from sea weeds). Actually the process for getting it in quantity from sodium chloride had already been invented in France, but what with revolutions and wars - wasn't put into use until 1820s, in England even a little later than in France, because of some special tax. On the other hand, potassium carbonate (potash) was very much in use, as it could be easily got and purified in every household from wood ashes. Since Middle Age a system of two barrels was used, called "lye-letch", ashes were put inside, and soluble mineral parts, with great proportion of potassium carbonate, were washed out of it. This solution would fulfil all functions of washing soda, and very well, too.

Soap was available, of course, and in various kinds, including translucent toilet soap, made by dissolving ready soap in glycerol and settling/drying the subsequent jelly in forms. In fact, soap was beginning to take lye's place in washing, when Napoleonic wars boosted the manufacture of textiles, where soap was needed in pre-dying process. The soap-makers worked like mad, the taxes on making soap went to three pence a pound; and in Cheapside the tax-collectors locked soap-boilers' coppers for the night, so that there wouldn't be any side production. Lye returned, at least for common people and boiling linen.

It was possible that big households boiled soap for their own use, then it would be made from lye and any fat available. Potassium stearate isn't very hard even when dry, so that soap would be not in pieces, but in bowls, but that doesn't mean that it must have been bad. In fact, it was better for the skin than industrial soap of those times, as home-made alkaline solution wasn't very strong, so fatty acids and glycerol, the by-products, weren't removed very successfully (product yield suffered, though). Nowadays glycerol and fatty acids are intentionally added to toilet soaps.

For silks soap was considered (and, probably, really was) too rough. In washing silks plants, naturally rich in saponines, were used. The best was West Indian soapbark (bark of Quilai plant), but European soapwort (Bouncing Bet) was much in use, too. Dry roots and even leaves, boiled in water, gave forth abundant - and delicate - foam.