In homes with hard water, mineral and metal deposits build up in the dishwasher's water lines over time and compromise the appliance's effectiveness. Calcium, rust and lime can also leave unsightly stains on the interior. Citric acid, a natural chelator, breaks down the deposits and removes the stains so your dishwasher looks and performs its best. The acid can also remove the white film produced by phosphate-free detergents and neutralize odors. Easy to obtain, non-toxic and environmentally friendly, citric acid can be used safely in plastic and stainless steel dishwashers.
Remove all patterned dishes and glasses, as well as metal items, from the dishwasher prior to cleaning it to avoid damage. You can safely leave non-patterned or non-metal items in the dishwasher during the cycle, though for stain removal, it's best to run it empty.
Pour 3 to 4 ounces of liquid or crystal citric acid into the dishwasher's detergent cup and close the lid.
Close the dishwasher and run it on a normal wash cycle.
Fill the detergent cup with your normal dishwasher detergent after the first cycle ends. Close the cup and dishwasher door and run another normal wash cycle to remove all of the build-up and citric acid.
Repeat steps two through four if traces of scale and scum remain.