1. Check the sprayer arm. When I opened the dishwasher door during a wash cycle, I learned that some of my utensils are too tall, and they blocked the sprayer arm from rotating. Problem solved! Also look at the holes on the sprayer arm to make sure they are not clogged. Use a toothpick if you need to dislodge anything.
2. Check the drain. Look inside the bottom of the dishwasher and remove any food or objects from the filter. Run the garbage disposal to clear it out before turning on the dishwasher since they share the same drain.
3. Don’t overuse detergent. It’s a mistake to assume you should always fill up the detergent cup. Check the manual and your detergent. On mine, filling it to the first line (about a third) is enough. Too much detergent can leave residue and etch your glasses.
4. Check your water temperature. If it takes a long time for the hot water to reach your kitchen sink, that means the dishwasher isn’t getting enough hot water at the beginning either, and that makes it harder to wash away the food particles and grease. If you need to, turn on the dishwasher after you’ve used hot water at the kitchen sink.
5. Clean the inside of your dishwasher. Grease, detergent residue, and calcium deposits build up inside your dishwasher. You can use vinegar to wash them away. On a regular basis (every few months or so), run a wash cycle while your dishwasher is empty. Don’t use detergent, but turn on the dishwasher and let it run for a few minutes until water starts to fill up the bottom. Then add one or two cups of white vinegar to the water and let it finish the cycle.
Sometimes using a dishwasher is an experiment in finding the right combination for hard or soft water, the detergent, and a rinse aid.