"Use a swirling motion"- that's apostasy!!!
I swirl rollers with one of those bastaardised spinning top thingies but would never swirl my brushes.
The centrifugal force maligns the hairs.
I flick them left and right (as you look at the brush). It is less effective at removing the water but the brush retains the shape it had when you took it out of the packet.
swirly things? :S you mean a roller cleaner which fires water in to spin the roller?