The oil can be cold pressed from the fruits or seeds which is a more costly than to extract the oil via the solvent Hexane. Using a solvent results in lower quality oil, and possibly may contain some of the solvent. Soap manufacturing most generally uses a solvent extracted oil due to the lower cost of production. Most handcrafted soapers prefer to use the higher quality, cold pressed neem oil. The oil is a brown-green and can solidify and need to be warmed up to liquefy.
Neem oil has been used for centuries in India especially in Ayurvedic traditional medicines. It is said to aid in the healing of several skin issues. Some research has confirmed that Neem seed oil is non-toxic to mammals and may effective as an antiseptic, antifungal, antibacterial and antiviral agent. A limited amount of Neem oil will go a long way, with about 5% being used in most bar soaps. It is often mixed with clays for facial soaps to treat acne or other skin problems. Neem oil is strong smelling with a hint of garlic or onions. It is not a pleasant odor! Many soaps with also incorporate essential oils to help mask the odor, but thankfully, soap is a wash off product!
Neem oil is also used in a variety of dog shampoo products to help with skin problems and to repel insects. Neem can be found in cat shampoo products as well. As a reminder, most dog shampoo products cannot be used on a cat. Cats are much more senstive to certain ingredients, especially any product containing essential oils, and some of these could actually be toxic to your cat.