Well, I just went ahead without advice, and I've been using a diluted apple cider vinegar + essential oil mixture, applying plenty when I start my shower, and letting it sit til just before I get out. Nothing to report, no one would know that I'm not using 'poo, but maybe overall a little softer. I just don't know enough about the chemistry to add or not add baking soda or something else. Or rather, I'm too brain dead from sleep deprivation to learn. Anyone educated/ more experienced/ less tired?