I have seeds for a few plants that can be used as soap. Soapwort, buffalo gourd, and another that I'm blanking out on the name of.
There are some flowers and herbs that can be made into a tea and splashed on the skin to help with body odor.
Another thing to add to the prepper repertoire.
Corn starch can be dusted on and is a great deodorant. I brush my teeth with baking soda, not because I can't buy toothpaste but because it works better for me.