Here's an article about how to make lye solution for soapmaking (or, apparently, as a catalyst for biodiesel): http://journeytoforever.org/biodiesel_ashlye.html

Note that the lye is potassium hydroxide, not sodium. The lye's reaction with fats is what makes soap, called saponification. I suspect a similar reaction is taking place between the wood ashes and the motor oil on your garage floors. Note also that the "proper" strength of lye solution is one which will [promptly] dissolve a feather, and it also attacks some metals.

Another article: http://www.motherearthnews.com/homestead...az72jfzfre.aspx

Last edited by Dave in Maine; 06/05/15 07:40 PM.
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