Abstract: A mold cleaner for in-line cleaning of a mold cavity of a blow mold of a blow molding machine. The cleaner has a mount attaching the cleaner to the collet of the machine, enabling the feed belt of the machine to transport the collet and the cleaner to and from the blow mold to be cleaned. An air-powered motor engages the mount, has a motor shaft, and receives air from the blow seal of the machine, which activates the motor and rotates the motor shaft. A bearing carrier surrounds the motor and engages the mount. A cleaning unit is carried by the bearing carrier and rotated by the motor shaft, and contacts the mold cavity to clean the mold cavity. A related method is also provided of using the mold cleaner to perform in-line cleaning of a mold cavity of a blow mold of a blow molding machine.