I do have the book and I believe in "doing things by the book" at least until you see how they are gonna work. Burroughs says this is a good thing to do but he also speaks against enemas and colonics which I think can also be beneficial depending on your specific experiences. I haven't done either while on this cleanse but I certainly have done them in life and would go that route during the cleanse if I felt it necessary.
I guess my feeling on this is that if you can shake everything loose without adding another "procedure" to the whole cleanse that is best but if not then her's a natural way to get the desired result. I didn't ever feel the need to go to that step while cleansing but maybe I just hadn't gotten to that level.