Most of us don't think about cleaning the dishwasher very often. After all, if the dishes are getting cleaner, shouldn't the dishwasher get cleaner, too? Unfortunately, debris and deposits do build up over time, and some of them reduce the performance of the dishwasher. Fortunately, dishwashers don't need cleaning very often and it's not hard to clean them. Here's how:
1. Use your dishwasher regularly.
It will help to prevent food and other debris from building up in there, reducing the need to clean it.
2. Run the dishwasher or wait until just after you've run it, then empty the dishwasher completely.
Do the other steps with the dishwasher empty.
3. Check all the spinning arms.
Look to make sure all the holes are open so that water can run through them freely. The hole in this photo has accumulated some debris.
4. Clear any debris out of the holes in spinning arms.
Use fine pointed or needle-nose pliers if you have some. Otherwise, try a toothpick or something similar. Take care not to scratch anything if you're using a tool with a metal point. If these holes are very small, bend a fine wire with a tiny hook on one end. Thread the wire through the opening most distal from the center of the arm. Each time you do this a small amount of debris will come out. This is time consuming. Another option is to drill a much larger hole at the end of the arm. Run the washer to eject the matter, then plug the bigger hole with a stainless steel screw.
5. Wipe around the edges of the door and around the gasket.
This space doesn't get washed during the dishwasher cycle. Use a damp cloth and, if you like, a bit of mild spray cleaner. An old toothbrush or other soft, household brush can help get into corners and up under the gasket.
6. Clean under the bottom of the door.
In some dishwashers, this is a dead spot where water doesn't go, so it can accumulate debris. Wipe this off.
7. Inspect the bottom of your dishwasher around the drain.
There will be a grate or grill around it, under the arm. This is where wastewater goes. Look for debris clogging up this area. You shouldn't have to clean this often if you're careful about what you put in your dishwasher, but you should remove any solid matter that builds up, especially bits of paper, shards of broken dishes, gravel, etc. You may be able to pick up solid objects accumulated on the outside by hand. If you think stuff has gotten down inside, you'll have to do some simple disassembly to get at it. Start by unplugging. These outlets have been labeled to reduce confusion.
8. Remove hard water deposits or scale, if needed.
Run one cycle of your dishwasher empty, with a mild, food acid of your choice. Do this after you've done the other cleaning steps here, so that it will also take care of anything your cleaning missed or knocked loose. A "light" or short cycle is usually sufficient. Place powders into the detergent cup. Place liquids in a right-side-up cup or bowl in the top rack. Use whichever of the following is on hand or inexpensive:
:: Lemonade drink mix or lemon-flavored Kool-Aid mix. Don't use strong colors that might stain. There is no need to add the sugar.
:: Tang (powdered)
:: Lemon juice
:: Distilled white vinegar
:: A dishwasher cleaning product
9. Remove mildew or mold with bleach.
Run a separate cycle from any acid cleaners you have used and never mix bleach with other cleaners or with dishwasher detergent.
- If mold and mildew is a problem, leave the dishwasher loosely open for a while after each cycle to allow it to dry out.
- Avoid using bleach and detergents containing bleach if your dishwasher has a stainless steel interior or door.
- Bleach is a very strong chemical, both on you and on your dishwasher, so use it sparingly and only when necessary.
10. Tackle rust stains.
- Use a dishwasher-safe rust remover  for the stains themselves, but ask how they got there in the first place.
- If the finish is chipping or flaking off the wire baskets in your dishwasher, try a paint-on sealant made just for dishwasher racks. Pull out the racks and check the bottoms, too. If the damage is severe or widespread (not just a few tines but all of them), see if you can replace the entire rack. Online stores sell a wide variety of appliance parts, so your replacement part may be very easy to find.
- If your water has a lot of iron or rust in it, rust may be beyond your control. If possible, address the problem at its source. If the problem isn't rusty pipes, water softeners can remove a limited amount of iron from water but they mostly work by exchanging minerals that are hard to clean off surfaces for salts that are relatively easy to clean. Filters do exist to remove iron from water and might be worth looking into if your water is extremely high in iron.
11. Spray the front of your dishwasher with a mild spray cleaner of your choice and wipe it with a sponge or soft cloth.
Pay particular attention to the controls and the handle. Also, don't miss the little ledge between panels. It tends to collect dirt.
12. Refill your dishwasher's rinse aid dispenser about once per month.
Rinse aid helps to prevent spots on your dishes. Unscrew the round knob in the dishwasher door and pour in rinse aid according to package directions or your dishwasher's manual. Depending upon your specific water chemistry, you may be able to substitute white vinegar for a "rinse aid." Experiment and see if this is right for your dishwasher.
:: Don't use rinse aid if you have a water softener.
:: Solid rinse aids are available. If you forget to refill liquid rinse aid, the solid ones are more visible, so they may help you remember.
:: If you prefer, some dishwasher detergents now have built-in rinse aid.
13. Clean the flatware basket with a brush if there is any accumulated debris.
Liquid dish soap will help.