[Mr Andrew (OP)]

Now, I know how you make soap with lye (NaOH), but where did the ancients get lye from?  I can't think of any naturally occuring OH- salts and all of the strong, Bronsted-Lowry bases I can think of don't occur naturally with soluble cations attached...CaCO₃, etc.  If they did, you wouldn't find them as crystals but dissolved in water and the ocean and rivers would likely be very basic.

[elegantlywasted]

Ash

[Karen W.]

Megs right... you leech the ashes( you soak them and let the drippings come through, like a strainer to a container below) and what is soaked out of the ashes is the lye for making your soap.. You can do this pretty easily at home for making your own soap. Lye soap is harsh, but it really cleans well.  I find straight wood ash is the best.. I don't know what others have used but this is the way I was taught..

[elegantlywasted]

Little tip.... after dying your own hair removing the colour from your forehead and ears is tricky. But if you dip a damp cloth into cigarette ash (or any ash i assume) and rub it on the colour, it will come right off... Granted you do smell a bit and the removal is a little scratchy, but it works like a charm

[Mr Andrew (OP)]

What's in the ash that makes lye?  Burning the wood releases carbon dioxide and water vapor and all that's left is the non-organic stuff.  I can't imagine that there's sodium hydroxide in wood so do you happen to know by chance what it is that precipitates to give a solution of sodium hydroxide after leeching?

[eric l]

Wood is more than just cellulose and lignin.  It also containsminerals from the soil it grows on, and some of these minerals are simply necessarily to growth.  So wood ash contains (among other minerals) potash (K2CO3)
See also :  http://en.wikipedia.org/wiki/Potash

[Mr Andrew (OP)]

Ah, that makes sense...ok, thank you.

[tony6789]

aleins brought it..lol