If only. Washing dishes incorrectly is a nearly universal experience, whether by hand or machine. Not that the two methods are mutually exclusive: 88% of households wash some dishes by hand, even if they have dishwashers, according to a new Mintel study. Both methods generally fall way short of cleanliness—and improperly washed dishes can lead to everything from illness to a flying cockroach infestation (seriously). Here are the 8 most common dishwashing pitfalls and how to avoid them.

  1. You forget to clean your dishwasher. Unlike cats, dishwashers aren’t self-cleaning. Solution: To get your machine super sanitary, run it empty with nothing but a shallow dish of white vinegar—which acts as an antibacterial—on the top shelf once a month, says Steve Ash, senior repairman at PartSelect.com. Run it on the hottest setting. 
  2. You don’t empty the food trap. (We won’t tell if you didn’t know you have a food trap.) “Too much debris will block adequate water flow and make the dishwasher significantly less efficient,” says Ash said, which results in still-dirty dishes. Solution: Clean it out every few weeks to stop mold and bacteria growth. (Hint: It’s under the spray arm at the bottom of your dishwasher.)  3. You don’t rinse. By tossing in dishes without rinsing them—and, let’s be real, letting them crust over before the next run—we’re asking for all kinds of trouble. “Ants and bugs don’t care if a piece of food has gone through the dishwasher or not,” says Mary Findley, author of The Complete Idiot’s Guide to Green Cleaning. If it’s on the plate, they’ll swarm. Solution: Rinse dishes before you load ’em. 
  3. You’re overcrowding. Does your lower rack look like the leaning tower of dishes? “Those can’t be getting clean,” Findley said. Overstuffing blocks water and heat, just like in your washing machine. Solution: Wash bigger pieces by hand. Place larger plates near the back and smaller ones near the center, so the spurt of water isn’t blocked, says Findley. 
  4. Your sponge is nasty. These innocent-looking rectangles are a bastion for germs, making your dishes anything but clean. Solution: Keep your sponges as clean as possible by washing them with antibacterial soap after each use and wringing them dry, says Mark Nealon, a restaurant consultant on food-safety practices. For extra sanitation, nuke your damp sponge in the microwave for 30 seconds. 
  5. You put the wrong things in the dishwasher. Dishes made of wood and ceramic can split or crack in the dishwasher, which gives an opening for bacteria to grow, says Ash. Also, beware of plastics. The National Institute of Health warns that polycarbonate plastics can break down at high temperatures, potentially leaching the hormone disruptor bisphenol A. Solution: Wash all plastics, woods, and ceramics by hand in not-so-hot water.
  6. Your sink is dirty. And not just dirtier-than-the-plates dirty. Experts say that kitchen sinks are dirtier than the toilets of public bathrooms. Solution: Every night after doing the dishes, Findley spritzes distilled white vinegar all over the sink (including the super-dirty faucet handles) and scrubs with a baking soda-topped brush for about a minute. 
  7. You think hand washing dishes is saving the planet. The opposite is true: Washing plates by hand actually uses more than six times as much water as an efficient dishwasher, and almost twice the energy, according to a European study.  Solution: For those items that you do have to suds in the sink, turn off the water anytime you aren’t using it. But remember that using an efficient dishwasher will leave far less of an eco-footprint—and it’s less work for you! More from Prevention: The Truth About Green Cleaners