Everyone with style 68 rims

Could all of you please tell me how you personally clean your 68's right here in this spot. This is the hardest spot for me to clean and no matter what type of "wheel brush" I have used none of them work as good as my index finger. I have bought 3 brushes now and everytime I find myself using my finger to get all of the brake dust off. Please tell me what you use so maybe I can find something that works for me.