Using a full dishwasher is more water- and energy-efficient than cleaning by hand. But be sure to use your dishwasher properly. Using too much detergent doesn't get dishes and glassware cleaner, it actually leaves a film on everything. Hand-wash items that can break, splinter or rust in the dishwasher -- things like wood cutting boards and bowls, cast iron pans, copper pots and antique glassware. And large items like cookie sheets and mixing bowls that barely fit should be washed by hand. They can block internal sprayers, making the entire dishwashing cycle ineffective.