The author shares her favorite office tool, a metal ruler, which she keeps in her kitchen drawer to keep surfaces spotless. Her grandmother's method involves using a triangular architectural ruler as a dry squeegee to remove dust from surfaces and transfer it directly into a dustpan. This technique is so effective that it costs nothing if you already have a ruler and is totally chemical-free. The author also uses a ruler to clean up dry kitchen spills and residue residue. The trick is most effective when the edge of the ruler is sharp, so metal or plastic work best.