The mechanics of a dishwasher may seem mysterious — kept hidden from view behind the machine’s door — but they’re actually simple. The basin fills with hot water, then a rotating sprayer arm in the bottom of the dishwasher pushes the hot water up and around your dishes. Once the machine is done washing, the water is pumped out through a drain. Some older machines have a final drying phase, where hot air is blown at dishes, but most modern dishwashers rely on the condensation of the water off the hot dishes to dry them.

Your dishwasher does a lot for you — but it still needs your help. How you load your dishes makes a big difference in how clean they get (and whether they avoid damage). These simple rules keep your machine running efficiently and as cleanly as possible.

Scrape off any large bits of food that might clog the dishwasher’s drain, but don’t worry about rinsing off every last speck — the dishwasher’s rinse cycle will take care of that. Plus, for the detergent to really work, it will need some bits of food on which to cling.

Run the hot water in your kitchen sink while loading the dishwasher. This ensures that the water running into the dishwasher will be hot right away, and it can start cleaning most effectively right off the bat.

Don’t machine wash anything made of wood — the dishwasher’s high heat and prolonged exposure to water will warp it.

Don’t overcrowd the dishwasher — too much, and everything won't get cleaned. Hand washing the one or two plates that don’t quite fit is easier than re-washing a whole load of partially cleaned dishes.

The more is not the merrier when it comes to detergent — follow the package's instructions. Use too much and your plates and cookware won’t come out cleaner, but the excess detergent (and excess water require to rinse it away) could wear your dishes down faster.

Seeing water spots? Try adding a rinse aid along with your detergent. If you notice that your clean dishes have a white film on them — don’t worry. You can blame hard water. Look for a detergent specially made to counter its effects.

When the cycle is complete, unload the bottom rack first so any accumulated water on the top rack’s dishes won’t spill on the dry dishes below.

Arrange these around the outside edges of the bottom rack so they don’t block the water and soap spray from reaching shorter dishes.

Load pots and pans facing down in the bottom rack first, then arrange smaller items around them. Most metal and glass cookware is dishwasher safe, but some nonstick and stainless steel pans may not be — always check the product’s packaging or manufacturer’s site. Avoid machine-washing copper and aluminum cookware, which can discolor in the dishwasher. Always hand wash cast-iron pans to preserve their seasoning.

Arrange plates and bowls in the bottom rack with their dirty side facing the center so they get the most direct spray of soapy water. Most everyday dishes — including ceramic, melamine, glass and heavy plastics — are dishwasher-safe. Be careful with vintage dishes, delicate china and anything with metallic trim, which the dishwasher’s high heat can damage.

Place cups and glasses upside-down in the top rack, making sure to place them between the tines, not over them — otherwise, the tines can chip or scratch glasses during washing. Avoid machine-washing crystal and delicate stemware, which can chip, crack or break in the dishwasher under the stress of high heat and harsh detergents.

In an ideal world, place all forks and spoons in the flatware bin handle-end down for the best clean. However, if you are washing a large batch of flatware after a party, you can avoid crowding and nesting by turning some less-soiled pieces handle-end up. Keep stainless steel and sterling silver utensils separate as the steel can pit the silver in the wash.

Load knives (barring pricey chef’s knives, which should always be hand washed) handle-end up to prevent anyone from accidentally grabbing a sharp blade.

Fully disassemble and rinse the bottles before washing. Place all the parts in their own basket on the top rack with openings facing down to get the most effective clean. If you want the dishwasher to sanitize your baby bottles, make sure your dishwasher has a sanitation setting.

Load any plastics prone to warping or melting in the top rack away from the dishwasher’s heater. Machine wash only plastics that are labeled dishwasher-safe.