How do I clean the interior of my dishwasher to remove white residue?

Monthly use of affresh® Dishwasher Cleaner is recommended to remove white residue and maintain the dishwasher. Place one tablet in the detergent dispenser (without dishes) and run a Normal wash cycle. Alternatively, place 2 cups (500 mL) of white vinegar in a dishwasher-safe container on the bottom rack and run a complete wash cycle without detergent, using the air-dry option. (Page 11)