Abstract: A brush core for use in cleaning a substrate is provided. The brush core includes an elongated cylinder having a first end and a second end. The first end of the elongated cylinder is configured to receive a drive hub. The second end is configured to receive fluid into an inner cavity of the elongated cylinder. The inner cavity is configured to distribute fluid to a plurality of fluid channels having a first diameter. The plurality of fluid channels are configured to distribute the fluid to corresponding distribution holes having a second diameter. The brush core further including a plurality of non-fluid distributing pockets defined on the outer surface. The corresponding distribution holes and plurality of non-fluid distributing pockets are configured so that a thickness of a solid portion of the brush core is substantially similar. In one embodiment, the first diameter is less than the second diameter.