Rasp

A drywall rasp is a hand tool with a serrated metal grate designed to shave small amounts off the edges of drywall (plasterboard) for precise fitting, smoothing rough cuts, creating custom shapes, and cleaning up edges around outlets, providing a consistent finish that's better than a utility knife for minor adjustments. It works like a wood plane, removing thin layers of gypsum and paper to ensure a perfect, seamless fit for patches or new installations, often featuring ergonomic handles and dust-reducing designs.