Wipe out as many clumps of congealed dishwasher detergent as possible using paper towels.
Fill a dishwasher-safe bowl with 1 cup of white vinegar. Set the bowl in the top rack of your empty dishwasher.
Run your dishwasher on a full clean-and-rinse cycle with a hot-water wash. The vinegar steam loosens soap scum and congealed dishwasher detergent.
Wet a sponge with water. Sprinkle baking soda over the sponge for extra scrubbing power.
Scrub the interior of your dishwasher with the baking soda to remove soap residue loosened by the vinegar. Use a toothbrush and baking soda to clean hard-to-reach places.
Wipe the dishwasher surfaces with a damp cloth. Dry them with another cloth.