[Al Skierkiewicz]

Many motors that allow you to change brushes will actually have two plastic screw covers in the case of the motor. You simply remove the covers and the old brushes pull out. Brushes are not exclusive to DC motors. Series wound AC motors like the type used in drills, saws, vacuums, etc. all have a brush assembly. When my daughter spent a year or two at Dairy Queen, I replaced a lot of brushes in the Blizzard machines for the owners. What a pain to work on and they ate brushes about every six to eight months depending on the time of year so I had them buy them at a dozen pair at a time. I would classify the Blizzard machine as severe duty motor use. Hard starts with a lot of ice cream in the cup, hits on the side of the stainless steel rings of the mix cup and a lot of start/stop since they are controlled by foot switch.
Your brushes are much smaller so I would guess at a hand drill or maybe a multi speed fan.