I'm posting this in response to several recent posts here because it applies to many. Give rye flour a try! In March I reached the 3-year mark of washing with a dilution of castile soap (Dr Bronner's lavender) and occasional ACV rinse. My scalp was often itchy and flaky and I had trouble finding balance. I decided I needed an occasional hot oil treatment and bought some jojoba oil, which was (and is, even on my face) nice but not enough. I tried water only for a while, but it never felt clean.
Enter rye flour! In my reading I finally stumbled upon discussion of this. I was skeptical, but tried it. Learned that without glutinous properties, flour doesn't become pasty. I tried chickpea the first time, because it was named as a good alternative and it's all I had that first time. It was so great. Body returned, itchiness went away. Apparently this is because it's pH balanced. Whatever it is, I've loved it for months now and recommend trying it if you're currently frustrated with your method.
I have fine, shoulder-length dirty blonde hair. I vigorously stir 1 rough Tbsp rye flour (the finest you can find in the bulk section—I only buy 2c at a time to fill a jar I keep under the bathroom sink) into about 1/2 c hot water in a cup that I take into the shower with me. I thoroughly wet and scritch my scalp, then turn my head upside down and dump the mixture over it. I turn off the water and keep scritching my hair, just as with shampoo. Sure it's grainy. Whatever. Finish your shower, rinse very thoroughly, finish with a cold rinse, and done. I have needed an ACV rinse in ages but your mileage may vary. I'm so happy with the results.
Another thing: I've been in an exercise class for the last month, so my routine is to shower and water wash at the gym every MWF. Right now I only rye wash once on the weekend. Totally happy.