Brushes are carbon brushes that remain stationary and deliver electrical power to the rotating part of the motor.
Relatively easy to replace and relatively inexpensive.
YouTube has a video that shows how...
http://www.youtube.com/watch?v=0GmtRBiXLFc
You find the motor brushes on the motor - the motor is deep inside the machine - often low down at the back.
Peccavi, June 2009