Successfully smoothing a finish depends on keeping your sandpaper clean by frequently brushing or blowing it off. Paper loaded with dust won’t cut properly. Worse yet, some finishes—particularly those that haven’t cured a long time—can cause “corns,” tiny blobs of partially cured finish that accumulate on your sandpaper and can mar the surface, defeating the very purpose of sanding. To ward off these problems, I keep the proper weapon at hand: a file card and brush. This combination tool, which is designed to clean files and rasps, sports a soft-bristle brush on one side and wire brush on the other. I keep it in my free hand while using the other hand to sand with paper wrapped around a felt block. When the paper loads up with dust, a quick swipe or two with the brush does the trick. I attack corns with the file card.
—Andy Rae, Asheville, North Carolina