Do you think Zest is the only bar of soap that won't leave scum in your shower? I still cannot convince my spouse to use liquid soap. Just trying to get an update here, after reading all the older posts about Zest.
We have hard water and prefer castile bar soap--it's made from coconut oil and doesn't form soap scum they way other (animal-fat-based) bar soaps do.
We like Dr. Bronner's, but Kirk's Castile is a good choice, too, and is less expensive than Dr. Bronner's.