Yuck. I had a lot of hair in the brush but that's normal too in a non-balding situation. Looking at the bottoms of hairs is not my favorite thing. I "love" it when people post pictures from their drains because I go to the gym to swim some times and eh clogged drains with body and scalp hair are not what I like to see. Your situation is strange though. Some guys claim to have sebum in the scalp literally underneath a certain layer and massage and maybe microneedling and wire brushing can like puncture the grape skin and let the fluid out but if it's hardened, maybe that contributes to male pattern baldness. Still we are left with no females basically in such a situation. We use to think sebum might plug follicles and maybe they don't plug them in a way that can be unclogged but they might also cause over-infestation by scalp flora who leave refuse that might cause inflammation.