I use a lye calculator that is found on line, as are many recipes. The site I like best is Majestic Mountain Sage http://www.thesage.com/index.html When made properly you have THE MOST luxurous soap you have ever used.......of course most of us have never really used SOAP.....instead what we buy is detergent! This soap will have NO lye left in it when the chemical reaction call saponification is complete (that's why I use a lye calculator).
I remember my Grandma's skin as being super soft, and smooth. She still made "her" soap, even when she could buy commercial bath soap at the store. Her's didn't smell, or look as pretty as the store bought bars, but she used hers on her face daily, and now I know why she looked like she did.
I will provide my recipe. I will also provide safety rules for making soap. It's a VERY safe project, but you DO need to understand what you're doing, and why.
I created this soap years ago (at least 10) when I tried some other "kitchen" soap made with coffee, but no coffee grounds.
This soap is GREAT at taking cooking smells....like Onion, Garlic, or Fish from your hands. It also works well (all though you may need to rince and repeat) removing the smell of oil, and gasoline!