Hair: I’m at the point of only using hot water now. I used to have really oily hair when I used standard shampoo. Transitioning from that, corn starch worked decent as a dry shampoo (I’d still rinse it out at the end) but it was messy and took a while for the corn starch to soak up all the oils.
Vinegar rinses left too much lingering smell, sometimes even after following up with baking soda. Baking soda alone seemed to strip my hair and have it extra frizzy. That was likely a result of the alkaline pH, as mammal hair tends to do better with slightly acidic pH. Now, hot water alone seems to have it at an optimal amount of natural sebum.
Body wash: I usually only use hot water in the shower too. I made my own bar soap with coconut oil, olive oil, and palm oil. If I need it, I’ll use it, but usually it’s unnecessary. Washing off sweat and bacteria doesn’t seem to be aided by a surfactant; put into other words, soap doesn’t do anything to “clean” your skin if you don’t have outside dirt and oil present. Hot water is enough to keep me smell-free (I have people that would tell me.)
Washing the skin with soap also seems to disrupt the body’s Vitamin D production/conversion process. That makes it seem to do more harm than good imo.
Hand soap: I made my own liquid soap with the same above ingredients (different hydroxide base used for liquid,) and glycerin. Great for dishes too. I use an emptied out Dial soap bottle with the foaming dispenser head because homemade liquid soap (like Castile soap) can harden in the air and clog the nozzle. Foam head fixes this.