This little guy comes with two miniature brushes that sweep from front to back when you roll it along, pushing dust, debris, and eraser fallout into the back compartment. It’s brilliant! Unfortunately, I couldn’t find anywhere online to order new ones (it’s made by “Midori” of Japan–you can guess how many companies have that name!). So far the only place I know you can get it is in the main stationery store in the Japan Center in San Francisco. Anyone know where else to get them?