A sandpaper block is a small wooden paddle with strips of sandpaper stapled to one side. It is used to sharpen pencils, charcoal or pastels, or to clean drawing tools, and can be an essential item for an experienced or developing artist.
In this regard, what is a sanding block used for in painting?
A block of sandpaper sheets fastened to a wooden handle for sharpening and pointing pastels and pencils.