Most of the recipes you will find today for soapmaking call for "One pound case of lye." Well, unfortunately, on the frontier, there were many times and places when cans of lye were not available. In fact, with lye being made from water and wood ashes, selling cans of lye on the frontier was like selling refrigerators to Eskimos.
First, one must construct an "Ash Drip" or "Ash Hopper". The hopper must be constructed of wood, as lye will eat nearly anything it is put in, except maybe glass or wood. At the bottom of the "v" put in an inch or two of straw or dried hay, so that the lye will not leak out into the drip container.
While stirring constantly in a Dutch oven or some appropriate boiling kettle, boil for 45 minutes or longer, if necessary, until it thickens, like jelly. As it is cooling, at this point, you may wish to add a few or several drops of peppermint oil to give it a pleasant smell. The soap has no unpleasant odor anyway when it has completely cooled, however, adding peppermint oils or other flavors were not uncommon. If a soft soap was desired, simply do not boil it so long, so that it does not set there, and a plank was placed on top, keeping out the weather. If a hard soap was desired, boil it down until it becomes very thick, then pour out into a shallow wooden box. When it has set up, cut it into bars or blocks with a sharp, thin bladed knife or wire. The time required for the soap to set up may be anywhere from overnight to a week or so longer.
This information was written by park staff.