Why Clean a Dishwasher?
It might seem strange to worry about cleaning an appliance whose job is washing dishes. But these handy machines need routine cleaning just like your other kitchen workhorses. That's because the door attracts fingerprints every time you load it with dirty dishes, and the interior (especially the corners and crevices) accumulates residue comprising food particles, grease, and soap scum. Not only do these deposits look bad, they eventually begin to give off an odor because of bacteria that thrives in warm, moist, and dark places. A monthly cleaning can keep your dishwasher looking like new.
Clean the Door
Keep the dishwasher door fingerprint-free by wiping the outside with warm, sudsy water. Or, use a homemade cleaning solution of 1/4 cup baking soda to 1 quart of water. Avoid harsh cleansers or too-tough scouring pads that might scratch the dishwasher's finish. When the door is clean, wipe it dry with a soft cloth.
Open the dishwasher door so you can get at its top and sides. Dip a small toothbrush in hot, soapy water, and scrub around the door. Make sure you dig into the grooves of the rubber seal and any other crevices, including the hinges. This step might require gentle scrubbing with abrasive cleanser. Wipe up the resulting grime with a household sponge dipped in hot soapy water. Wipe away any cleaning solution left behind with a clean, wet sponge.
Clean the Tub
Before you start cleaning the tub, use a handful of paper towels to grab any debris from the base of the dishwasher. You'll find most of the debris around the drain.
Once the debris is removed, set a dishwasher-safe cup of plain white vinegar on the top rack. (The dishwasher should be otherwise empty.) Run a full cycle, choosing the hottest water possible to disinfect the unit while it's being cleaned. When the cycle is done, wipe out the inside of the dishwasher with paper towels or a clean, dry cloth.
In place of vinegar, you can either put a packet of unsweetened lemonade mix in the soap cup or sprinkle a cupful of baking soda on the bottom of the tub. For either method, run a complete cycle using the hottest water possible. Either option will help clean and freshen your dishwasher.
Clean the Accessories
Your last step? Cleaning the accessories. Take out the racks and utensil holders. Wipe off any stuck-on food particles or other debris. Scrub the spray arm with a soft brush or toothbrush to remove clogs.
Troubleshooting: Rust Stains
Depending upon your water source and the state of your pipes, you might see mineral or rust stains inside your dishwasher. Check the laundry detergent section of your home center for products that remove rust stains from clothing or appliances. Place the product into the soap dispenser cup in your dishwasher and sprinkle some freely on the bottom. Run the empty dishwasher through a complete cleaning cycle.
Since the source of rust stains is systemic (e.g. your water comes from a private well or your home's pipes are rusty), you will likely need to repeat this process on a regular basis unless you take care of the problems at their source. You might also want to ask a plumbing contractor to install a filter that can help with rust control.