Another Sam is weird story: I realized I wasn't going to have enough Dr Bronner's so I looked around the apartment for something else that might work and decided that the liquid dish soap that is "lavender-mint" would probably be fine since I use peppermint & lavender Dr Bronners mixed together and the ingredient list looked reasonable. And lo and behold it seems to have worked well (I also chucked in plenty of baking soda + water in with the soap). It seemed to foam up better than Dr Bronners so maybe I'll try it again? Though I don't have much of this left either...