The casters had become dirty with an assortment of debris, sometimes the dust on the floor will sticks on the surface of the caster due to rolling, and the black crumbs or debris fall during the movement of the casters. In fact, the debris combines with the normal amount of dust and hair that accumulates on the floor, so the debris is not peeling off from the casters. Please follow the steps below to clean the casters.
Step1: Sweep/Vacuum the floor and Mop the floor. The dust on the floor is the mean reason that makes the caster wheels dirty, so highly recommended clean the floor before you clean the caster wheels.
Step2: Use a rag to clean caster wheels. wiped caster wheels over with a damp rag.
If you want to keep the caster wheels clean, please sweep/vacuum the rooms often and clean the caster wheels once a week.