Conair Professional - Babyliss Scalp Massage Brush
Denman - Denman D3 Classic Styling Brush 7-Row
I used to struggle with scalp itchies with co-washing and would low poo often. No matter how much I scrubbed with the pads of my fingers it was never enough and I would end up with little white flakes at my scalp which was not dandruff. You can just massage with the scalp brush if you don't want to run it through your length but I never have build up issues anymore and low poo LESS since I started using my shampoo brush or denman. I think a lot of people afraid to use them because it's not supposed to be "CG" but who cares?
You can still co wash or use botanical cleansers and shampoo less. The ultimate goal is to have healthier hair. So go ahead pick and choose what CG means to YOU by incorporating some or all of the original CG method and you'll be happier.