What Causes Mottling on Stainless Steel Flatware in a Dishwasher?

Pre-Washing

• Salty or acidic food can cause discoloration of stainless steel flatware. This discoloration occurs when these foods are left on the surface of the flatware for long periods of time before actually running the dishwasher, according to the Towle Stainless Flatware. Tea, coffee, mustard, mayonnaise and eggs are just a few foods that can pit or discolor stainless surfaces. To avoid this problem, rinse flatware carefully before loading into the machine.

Dishwasher Loading Problems

• Improper loading can always cause mottling stainless steel flatware when the detergent and water cannot flow over flatware surfaces. Always place forks and spoons with handles downward and tines and bowls pointed upward. Always place knives into a separate basket compartment with the points downward to prevent injury.

Lime Deposits

• Hard water in a problem in some areas of the country. The minerals in hard water can cause lime deposits, rusting and mottled stains on flatware. If hard water causes staining on clean dishes and flatware, consider installing a water softener for home. Water softeners can help to preserve the life of your appliances and removes the minerals that cause stains on flatware and clothing.

Metal Interactions

• Different types of metal can react on surfaces when they are in contact with water and detergents within the dishwasher. Stainless steel flatware should never touch other metals within the machine. To be on the safe side, you can avoid mixing different metals in the same washload altogether, according to flatware manufacturer Oneida.

Hot-Air Drying

• Using the hot air drying cycle of your dishwasher can also create discoloration and mottling of stainless steel flatware. Simply air dry the flatware for best results.

Removing Stainless Steel Flatware Stains

• Do not use cleaning products that contain lemon or other citrus oils that can damage surfaces. Polish your stainless steel flatware with a small amount of household vinegar poured onto a soft cloth. For severe dulling of the stainless finish, mix 1/4 cup of chlorine bleach and 1/4 cup of water softener and 1 gallon of hot water. Immerse the flatware into the mixture for 30 minutes, then wash by hand with dishwashing soap or load into the dishwasher and run a normal cycle. A paste of baking soda and water can also be used to polish stainless steel flatware.