I used to make soap back in 2000-2002. But for some reason, here in Florida the lye was taken off grocery stores shelves, and at the present time it's almost impossible to find any. All lye-based products still sell, but not the ole Red Devil, or similar pure lye that can be used for soap.
The soap I made, even with essential oils, always smelled like unscented Ivory soap. We used it to wash the dogs, and hands. Whoever said above that it's great for taken heavy duty stuff off the hands is right.
I stopped making soap mainly for the shortage of lye. But, also because when I ordered essential oils from a Canada website, after 911, the package almost caused an international incident. Someone thought the essential oils were chemicals for bombs, or something.
So, that swore me off of buying stuff like essential oils online. Though I found a good website based in India that sells bulk for affordable prices. I guess that buying from them could still put me in a terrorist watch list, or something.
Buying essential oils in this area can cost more than buying pure gold.
I could pick up the hobby again, if I were to find a local lye source.
I don't know of the "cold" method, but I'm going to dig into it.