I have a 5 foor long 'wash brush' with those wonderful pre-beaten fuzzy poly ends on the bristles. Very soft, I'm comfortable using it - although the dirt on the sides of the car worries me.
I don't like those molded foam pushers some folks recommend - seems like you'd just be asking for the little particles to scratch up your paint as the get wedged between the 'brush' and the paint.
Bob