I tried a castile soap that I purchased from a organic health store on my hair this morning and had some problems with it.  When I put it in, it smelled so nice and lathered nicely for about 30 seconds and then it would no longer spread in my hair and lather.  So I thought, there are some concentrated poos that don't lather and still work good so this did not discourage me yet.  I then washed it out and my hair felt coated with something and very tangley and dry.  So put lots of heavy conditioner on and rinsed after a few minutes.  It did not feel any better.  I got out of the shower to try to comb it and I could not comb it, even with a lot of leave in conditioner.   So I got back in the shower and pooed with my regular shampoo 2X to get the stuff out and condtnd.  My hair feels better now but a little drier than normal.  I personally think that it would work for a clarifier to use before using your regular, moisturizing poo.  My hair doesn't feel coated any more.  I don't think I would recommend this, unless I am using it wrong.  Suggestions?  Here are the ingredients:

18 in 1 hemp peppermint pure castile soap-H2O, saponified coconut and olive oil with retined glycerin, hemp oil, jojoba oil, peppermint oil, mentha arvensis, citric acid, vitamin e (all organic). 

Are you talking about Dr. Bronner's Magic Castile Soap? I hope not.

PLEASE don't put that on your hair.

I wash my hands with it and my combs/brushes. It's the only thing that "DE-GREASES" very well. It takes all of the oil out of my brushes, I can only IMAGINE what it does to hair.

I would only suggest that once a week if your hair was VERY, EXTREMELY OILY and fine. If you have curly, African, or dry hair, this could very well be your hair's WORST ENEMY!