Step 1: Clear the drain
Remove the bottom dish rack. Inspect the dishwasher drain, removing any gunk or food caught there. This will improve drainage, increase cleaning efficiency and prevent damage to the dishwasher.
Step 2: Vinegar wash
Start with an empty dishwasher. Place a cup of white vinegar in a dishwasher-safe container on the upper rack of the machine. Run the dishwasher through a hot-water cycle. This will wash away grease and grime and remove musty odors, too.
Step 3: Baking soda rinse
Sprinkle one cup of baking soda across the bottom of the dishwasher. Run a short, hot water cycle. The dishwasher will be fresh-smelling and have a brightened, stain-free interior.