An automatic dishwasher is more energy- and water-efficient than washing by hand. But if your dishwasher isn't doing the swell job it once did when you first got it, it may be time to wash the dishwasher. Start by filling a large glass with white vinegar and propping it upright inside. Run the dishwasher as normal, and the vinegar will help break down stains and buildup inside. Also, propping the dishwasher door ajar after each use will help keep the inside free of mold and mildew.