How do I know what can be washed in a dishwasher?

Look for a dishwasher-safe imprint before you place items into your dishwasher. Pay particular attention to plastic food storage containers, which can melt if they come into contact with the heating element at the bottom of the dishwasher. If you're not sure, put them in the top rack only or wash them by hand. If a piece of plastic melts to the heating element, it can be tough to remove it.