Step1:
Power off the robot.
Step 2:
Remove the side brush by pulling it out.
Step 3:
Then carefully unwind and pull off any hair or string that is wrapped around the side brush.
Step 4:
Use a cloth dampened with warm water to remove dust from the bristles of the side brushes and reshape them gently if they are bent.
Step 5:
Replace the side brush by putting it on and pressing it down to the robot.