Keep your drill bits in tip-top shape by cleaning them whenever necessary. This task is easily accomplished by wiping them with a clean cloth after use (wait for the bit to cool down first) or for more stubborn grunge, using an old toothbrush to scrub away sawdust, drywall dust, or other caked-on materials.  If your drill bits are rusty, submerge them in a bath of white vinegar for at least 30 minutes, and then use an old toothbrush or a metal cleaning brush to scrub the rust away. Rinse the bit thoroughly in clean water, and dry completely before using it or storing it.