I've made hobby type soap in the past but find similar problems with getting lye for many years. I just use craft supply stuff as a teaching project for my granddaughter. I did make a mistake once long ago by putting too much dried lavender in my bars. LOL. Can we say rough?
My great grandmother made hers in yard using
homemade lye...she told me they made it from wood ashes. I remember her telling me that she "tasted" the soap...can't remember if it was to tell her when it was ready to cut or when it was cured enough. While I was interested enough to ask her about it...I sure didn't know enough to ask questions on *HOW* that was done. Sometimes the details don't make sense till you actually try making an old craft...that's when all the little questions start popping up. I'm sure if they could make lye way out in the brush a long wagon ride to anywhere, that it wasn't too difficult...LOL. I know she saved up "grease" that was past it's prime over the year as one of the ingredients. I don't think "oil" was something they would have had access to...I never saw it used until the 70's in my family. So lard was the main fat other than butter and who would use their precious butter for soap? I remember my Mom talking about the smell of the yearly soap making which was done in January in N Texas which was hog killing time back then.
Something that alot of the younger folks don't know is that used grease/oil was a commodity and was (and possible still is) collected from many places (school cafeterias, restaurants, byproduct industries, etc, for pouring down sewers/septics were NOT good) and it was then sold to make soaps and cosmetics and such. There actually was businesses that their whole job was picking up barrels of the used grease/oil from these establishments. What they did with or how they processed it for selling I can not tell you. I saw a Modern Marvels (history channel) show about Pigs and they said that up thru the 1950's most of the hogs raised in the US were raised for their lard for not only cooking but industrial applications such as soap.
My family oral tradition is that eating lye soap was a
cure for rattlesnake bite...my mom's dog was called "Rattler" and he was known to eat lye soap when he got bit, which apparently happened a few times. I can't imagine how lye soap could possibly "cure" such a thing....but perhaps there is something in the story.