How to Clean Your Dishwasher

A dishwasher that's properly cleaned will function more efficiently—and perhaps last longer, too.

Photo: Bryan Gardner

The dishwasher might be the one thing in the kitchen that works harder than you. Return the favor and learn how to keep it functioning efficiently and looking spic and span with our comprehensive guide to cleaning it inside and out, thanks to Martha's Homekeeping Handbook ($24.36,

Cleaning the Exterior

Once a week, clean the dishwasher's door panel with a soft, lightly dampened cloth and dry thoroughly. Stainless steel can be cleaned with a commercial stainless steel spray. To clean the control panel, use a lightly dampened cloth (excessive moisture can damage the panel) and dry thoroughly.

Getting Rid of Mildew

To remove mildew from the interior or gasket, mix one part chlorine bleach to 10 parts water, or mix one gallon of water with 1/2 cup of ammonia. Then wipe with a cloth or sponge, wearing rubber gloves. Note: Never mix bleach and ammonia together. Doing so will result in dangerous, potentially lethal fumes. Don't use chlorine bleach to wipe out mildew if the machine has a stainless steel interior; bleach can corrode it. Run the dishwasher through a rinse cycle to remove any residual cleaner.

Removing Rust Stains

Rust is usually caused by iron and magnesium in the water. It can also come from a rusty water heater or rusty water lines. You can check for iron and magnesium by having an analysis done by a water treatment equipment company or testing laboratory. To find a local facility, contact your local cooperative extension system office. They should be able to tell you how to obtain a sample of your water and send it in for analysis. To remove stains, try a commercial rust treatment. As a preventative measure, ask a plumbing contractor to install a filter that can aid in the control of rust.

Dealing With Brown Stains

Probably caused by calcium or iron buildup, brown stains can be managed with citric acid (also known as sour salt) in liquid form, which is available at some large grocery stores (it was once widely used for canning) and many health food stores. Empty the dishwasher, fill the detergent cup with your citric acid, and run a complete cycle. Run the dishwasher through a second cycle without the crystals, but with detergent.

Treating Red Stains

Mostly caused by a tomato-based product, this kind of stain might be permanent, but should fade over time with repeated washings. Minimize staining by removing any excess sauce from your dishes before loading the dishwasher.

Eliminating Green Stains

Caused by detergents that contain dye or color pigments, green smudges can be remedied easily—simply switch to another detergent.

Managing White Film Buildup

This is caused by hard minerals and, over time, can damage other components of the dishwasher. To mitigate this, install a water-softening system. You can temporarily remove the buildup by using citric acid, as directed for brown stains.

Washing with Vinegar

After treating any stains, clean the interior of your dishwasher: Take the racks out, and use a toothpick to clear any gunk from the holes in the spinning arms. Wash the grate where the water drains, as well as the removable filter (if there is one) with warm, soapy water. Wipe the rubber door seal with a damp cloth soaked in vinegar. Sprinkle one cup of baking soda on the bottom, then run the machine on a short hot-water cycle to clean any remaining stains and odors.

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