One of the leading natural "green" soaps is based on Goat's milk.
Goats Milk Soap typically is made from all natural ingredients and no harsh chemicals. Ingredients usually consist of Saponified (the chemical reaction that occurs when oil is mixed with alkali, don't worry, there is no * lye in the final product, it is neutralized in the process and forms the soap and glycerin) and 100% food grade olive, coconut, palm and castor oils, all in a goat's milk base. Pure essential oils and mineral pigments lending a scent may be added.
Goats Milk Soap is usually all handmade, not using any of the mass- produced processes or machinery.
Milk is known as a skin moisturizer and rejuvenated. Since Egyptian and Roman times, olive oil has had a reputation of enriching the skin and being a major part of the beauty ritual.
A lot of handmade and high end soaps retain the Glycerine, using the "Cold Process" and they are very mild and actually can help people with skin problems to over come them. Glycerine is very good for children and those with sensitive skin.
Handmade soap can help those who suffer from eczema and psoriasis.
There is a growing movement to go back to more natural, handmade soaps such as Goats Milk Soap than those mass manufactured. There are a lot of ingredients in mass manufactured soaps that can cause irritation to the skin in some people. A main ingredient for this type of soap is Tallow (beef fat). Tallow is cheap, and also forms a "hard" soap that lasts a long time. Some soap can also contain Isopropyl Alcohol, Alkali, DEA, BHT, and Triclosan (an anti-bacterial soap ingredient). These chemicals can be the reason the skin can feel itchy, tight and dry.
The more expensive mass produced soaps may still contain Glycerine, which is very beneficial for the skin to stay healthy, smooth and soft. Glycerine is actually a by product of the processes used to make soap. Lower priced soaps have the Glycerine removed and put it into other products such as creams and lotions that can be charged more for.
* Mass produced soaps can still contain some Lye.