Remove the brush bar. It's designed to come out for cleaning.
FIX: Disconnect the machine from the charger first. Press the cleaner head release button on the wand. Place the cleaner head upside down. Locate the end cap on the side. Push it up fully. Pull the brush bar out of the cleaner head. Remove the end cap from the brush bar. Do not wash the end cap. Clear all hair and debris from the brush bar by hand.
Wash the brush bar under running water, gently rubbing it. Squeeze out excess water. Stand it upright with the closed end at the top. Let it dry completely for at least 24 hours.
Before replacing, ensure the brush bar is bone dry. Reattach the end cap. Slide the brush bar back in. Push the end cap down to the closed position.
IF THAT DIDN'T WORK: For the Mini motorised tool, the process is different. Use a coin to twist the end cap anti-clockwise, remove it, and slide the brush bar out. Clear debris. This tool and its brush bar are not washable—only wipe with a damp cloth.
HEADS UP: Never submerge the cleaner head itself. It contains electronics.