I liked your write up!! You reminded me of the PH concerns for skin vs the hair itself in the clarifying shampoos!Alrighty boys and girls. I was getting pretty twisted with all this info plus all the info online so I did some research and a very unscientific test. What prompted this was this morning I went to use one of my boar brushes and it felt yucky. So I dug in. Here's what I learned.
Most written information out there in dealing with cleaning hair is about hair that is still attached to the head. This is very very different than hair used when not on the head. For example, I read to use dog shampoo since a dog was an animal and boar was an animal. Let me tell you that most shampoos deal with the pH of skin first and then clean second. That's why you can't use people shampoo on dogs.
Baking soda is very alkaline and all real studies has shown that over extended usage will damage the hair strand. That's why it's so good at stripping out bad junk from hair. Ok so no baking soda (for me).
Vinegar is a very mild acid which is why it's so good at cleaning. Almost all of the packaged brush cleaners use lye. I deal with lye in soap making and sometimes at work. It can be pretty nasty stuff if not used properly. I'll stick to vinegar.
Dish soap is about as mild a detergent as it gets. I use vinegar and Dawn to clean a lot of things including including a lot of shaving related items. Nowhere did I read anything that contradicts the mildness of this cleaning solution.
I read that clarifying shampoos were designed to strip away junk from hair and scalp. After digging in on those I found one that was designed to remove hard water specific minerals as well as soap buildup. I went with that one. It is Living Proof Perfect Hair Day (PhD) Triple Detox Shampoo.
I did two tests, one with the clarifying shampoo and one with the vinegar and Dawn solution.
I had two brushes that felt about the same level of yucky: a Semogue Galahad and a Semogue Excelsior 830.
I presoaked both brushed for 20 minutes in tap water.
I mixed up a solution of 2 C distilled water, 2 tsp. vinegar, and 4 drops Dawn. I added that to my small ultrasonic cleaner. I ran the Galahad in the ultrasonic for 5 minutes and then thoroughly rinsed with tap water and pressed out as much water as I could with a towel.
With the 830, I added a pea sized amount of the clarifying shampoo and thoroughly worked it into the bristles. I put 2 C of clean distilled water into the ultrasonic and dropped the soapy brush into it and ran it for 5 minutes. I rinsed and press dried as above.
I then put both brushes in front of a desk fan for 1 hour to dry.
At the end of the hour both brushes felt soft and clean. I could not tell from feel if one was cleaner than the other.
I use both, a scuttle and bowl. I am not a face lather'er. I used my favorite soap from Soap Commander that I use 90% of the time. I built lathers with both brushes in both vessels thoroughly cleaning the brushes and bowls between lathers.
This produced very different and discernable differences.
The Galahad (cleaned with vinegar and Dawn) produced whip cream like lather with small bubbles that held up to standing for a few minutes even in the hot scuttle.
The 830 (cleaned with the clarifying shampoo) produced a rich later but had noticeably larger bubbles and it was the usual flat mess needing to be rewhipped in the scuttle.
There you have it. That was my very unscientific test based on my situation and conditions. As always, YMMV.