I don't worry so much about the cleaning of the bow as I do scratching it up with the string. I have wondered and pondered if this is a technical problem in my playing. I have tried other bow grips and angles and amounts of pronation and have come to the conclusion that it is a choice, and aesthetically best for me. It suites my body and my strenghts best. Not all the time, of course. Sometimes a flatter bow is called for. But I do a lot of orchestral playing, and in order to blend well and be precise, but not too bold...my bow gets pretty gungky.