I`ve got 100ml white birch tar essential oil arriving today so it`ll take me less than five minutes to put it in a liquid castile soap base and I can add lime to it for shaving or shampoo.
It`s very expensive but worth it - I`m a medical herbalist so I have a lot of concretes, absolutes and eo`s.
It`s a bit like Wrights coal tar soap but much more versatile and efficacious.