Abrasive sanding belts are too expensive to toss out every time one becomes clogged with wood dust. In most cases, the abrasive surface can be cleaned and reused many times.
You can purchase a belt-cleaning stick ($8)—it resembles a giant pencil eraser — through most woodworking catalogs, but we've found a less expensive, more "soleful" solution.
Take an old crepe-sole shoe and use its rubbery tread to clean the clogged sanding belt. Clamp the sander upside down to a workbench. Turn it on and very lightly press the crepe sole against running belt. Slowly move the shoe from side to side to clean the entire abrasive surface. Caution: Be sure to remove and discard the shoelace so it can't become caught in the running sander.