Q: What do I need to do to clean and maintain my dishwasher?

A: Cooking and dining at home can be a joy, except for the last step: cleaning up the mess. That’s where a dishwasher can be a godsend. But sometimes the dishwasher itself needs a little cleaning up — by you.

From a functional standpoint, the most critical place to clean is the filter at the bottom of the dishwasher. For years, main U.S. brands featured nonremovable filters, which they advertised as self-cleaning. The holes or grid openings on the filters were quite large, letting most food debris through, because the dishwashers also had grinders (think tiny garbage disposals) to reduce chunks of food to small particles that wouldn’t clog the pump or drain line. European models, meanwhile, typically had filters that needed to be cleaned manually.

Some consumers saw that as a disadvantage, but many still bought the machines, because they were quieter. A key reason: They didn’t have grinders. As noise rankings became a major selling point, the market shifted. Although some dishwashers sold in the United States still have nonremovable filters, most now have manually cleaned filters, or at least filters with a part that needs to be cleaned manually.

“Energy and water standards, as well as overall system performance, contributed to the shift in filter design,” said Jill Notini, vice president for communications and marketing for the Association of Home Appliance Manufacturers.

If you have a model with a nonremovable filter, make a habit of regularly checking the grate or cover at the bottom, underneath the twirling spray arm. Although the holes let food through, the filter is designed to block larger, harder debris, such as toothpicks or olive pits. Cleaning is easy: Just pick the pieces out by hand. Some Frigidaire models with self-cleaning filters don’t have holes where hard bits collect; instead, below the spray arm is a so-called glass trap that filters out broken glass as well as pits and other debris. To remove and clean this piece, turn its handle counterclockwise 90 degrees while pressing down on the center of the spray arm.

If your dishwasher has a removable filter, check the manual (or find it online, usually via the manufacturer’s website), because specifics vary. There is generally a circular piece at the bottom of the tub that’s easy to grasp with one hand and turn counterclockwise when you want to inspect and clean the fine-mesh basket strainer underneath. The counterclockwise feature isn’t uniform, though: Some turn clockwise.

The circular piece often fits into a flat piece of metal mesh with coarser holes that lifts out for cleaning. Clean each part by rinsing it out in the opposite direction from the way the water flows when the dishwasher is running. An old toothbrush or other soft-bristled brush, or a sponge, can help loosen debris. Soaking a part in soapy water might also help. If there is mineral buildup, soak it in vinegar. Once you’ve removed the metal mesh, clean the area underneath to remove any bits caught there. Some Samsung dishwashers also have a door below the metal mesh that opens to allow for the cleaning of debris.

Besides cleaning whatever is at the bottom of the tub, you might also need to clean a part called an air gap that is next to the sink, higher than the dishwasher. The air gap has a liftoff cover, and below that is a part that’s plumbed to both the drain line from the dishwasher and a drain line that connects to the sink, with a small air space separating the two. The gap prevents drain water from flowing back into the dishwasher, which would stink and could be a health hazard. (Some installations don’t include this and instead rely on a high loop in the dishwasher drain line to prevent contaminated water from draining back into the dishwasher.)

When there is an air gap, food particles can build up and block the gap, preventing the dishwasher from draining properly. To clean this, remove the cover and use tweezers or a narrow brush to remove debris from the plastic part underneath. Or try a plumber trick: After you remove the cover, place a cardboard tube from a paper towel roll over the plastic mechanism and blow through the tube with as much force as you can. Using a wet/dry vac over the plastic is a third option for clearing the tubing.

Other than the filters, a dishwasher usually cleans the interior on its own, as you do dishes. But there’s a chance the nozzles on the spray arms can become clogged with mineral deposits or even food. Clean these by removing each arm (most dishwashers have upper and lower ones) and using a narrow wire, a pick or a sturdy needle to clean out the holes while running water through the central opening on the arm. You might also need to wipe around the gasket periodically with a damp cloth. Some manufacturers recommend running a cleaning cycle periodically with no dishes but with citric acid, vinegar or a dishwasher cleaner to break up mineral deposits and remove films or stains from hard water.

No dishwasher can clean its exterior, though. That’s up to you. You can never go wrong by simply wiping away food spatters with a soft, slightly damp cloth, then drying the surface with a second soft cloth. Use a little hand dishwashing soap diluted in water if you need something more powerful, but rinse away all the soap by going over the surface with plain water. Beyond that, it’s important to know what type of finish is on the door. Some dishwashers are painted — a category that GE’s manuals say includes black stainless steel and fingerprint-resistant stainless steel. On these, never use a stainless-steel cleaner.

It’s okay, though, to use a stainless-steel cleaner on a door that is regular, uncoated stainless steel. It’s also okay to use baking soda and water. And if there is tarnish or rust, you can use a nonabrasive cleaner that contains oxalic acid, such as the soft cleanser from Bar Keepers Friend. Rub in the direction of the metal grain lines. Never clean stainless steel with chlorine bleach; the bleach destroys the chromium oxide layer that forms on stainless steel and makes it rust-resistant.

Have a problem in your home? Send questions to localliving@washpost.com. Put “How To” in the subject line, tell us where you live and try to include a photo.