I said rarely because i don't usually try. There are several reasons. One is because a single pass(not all strokes in one direction though) with dedicated touch up is almost as good. To get a good cleaning stroke on my problemos my hand blocks my eye and i have just recently figured how to do it.

When I say rarely I mean never as some of those problem areas are not bristles they more like gristles which i cant cut smooth no matter what I have tried