How do I clean the interior of the dishwasher to remove hard water film buildup?

Make a paste with powdered dishwasher detergent on a damp sponge and clean the interior, or use liquid automatic dishwasher detergent with a damp sponge. Alternatively, you can run a white vinegar rinse by placing 2 cups (500 mL) of white vinegar in a glass or dishwasher-safe measuring cup on the bottom rack and running a complete wash cycle without detergent. Always run a normal cycle with detergent after cleaning the interior. (Page 18)