I felt comfortable taking regular dish detergent in a small bottle. Al long as it doesn't contain any phosphates it should be environmentally sound, and virtually no soaps contain this stuff any more. Sgt Rocks sight even mentions that a chemist freind of his testified to the fact that it's pretty much all the same. Beyond that I'd say get soap with as little scent to it as possible. And if you have long hair bring along real shampoo, just a little for use in town.