If you are doing this with the bike assembled, take some rags or newspaper and cover the other parts of the bike.the tiniest little droplets will flip off your brush as the bristles flex and straighten and you will have to clean it off the bike if you don't. Not much work to clean, especially on a heavily waxed bike, but no need to do it if you cover the frame, wheels, brakes, etc.
Tom Sanders
Lansing, Mi USA