Take the dishwasher filter apart and clean it thoroughly. Remove the internal pieces according to the manufacturer's instructions. Soak the plastic filter in a sink full of hot, soapy water for 30 minutes to soften any baked-on particles. Scrub the filter with a cleaning sponge and let it air dry. Replace it according to directions.
Wipe down the inside of the dishwasher with a mild cleanser spray and a cleaning rag. Focus on the corners of the dishwasher, as well as the space around the door seal. Get rid of any food particles, black mold and slimy buildup using the cloth. Wipe the inside down with a clean wet rag to eliminate any cleanser residue.
Run a cycle of the dishwasher using powdered citric acid. Start the cycle when the dishwasher is empty. Pour the powdered citric acid into the detergent cup and close it. Run the cycle as normal, then check to see whether the white grainy buildup on the heating element is gone or significantly diminished. If not, run another cycle using the citric acid.
Add citric acid to each load of dishes you wash. Pour powdered dishwashing detergent into the cup until it is halfway full. Fill the other half with the powdered citric acid. If you use a dish detergent tab, place the tab on the floor of the dishwasher and fill the detergent cup halfway full of citric acid.
Run the water in the kitchen sink on hot for one to three minutes before starting the dishwasher. This clears out any lukewarm or cold water from going into the dishwasher and allows hot water to enter the unit immediately. Dish detergents dissolve better in hot water and are less likely to leave gritty residue on dishes.