A floor cleaning device is disclosed. It comprises a brush, which is rotatable around an axis of rotation, and a cover having a cover surface which faces the axis of rotation and has a plurality of ridges constituting liquid channels between them for transporting liquid to outfalls provided at lower ends of the liquid channels. In addition, a method of cleaning a floor is disclosed. The method comprises the steps of providing a brush, bringing the brush into contact with the floor, moistening the brush with a fluid, for example, a cleaning solution, rotating the brush, collecting droplets of fluid, released from the brush due to a centrifugal force associated with its rotational motion, in a plurality of liquid channels provided on a cover, and guiding the collected fluid through the liquid channels towards outfalls provided at lower ends of the liquid channels.