The black marks at the top of dishes in a dishwasher can be caused by several factors:
Heating Element Damage: The heating element in the dishwasher can become damaged or corroded over time. If it's not functioning properly, it may cause the top rack of dishes to remain cooler than the bottom rack, leading to inadequate drying and leaving black marks.
Plastic Items: Plastic dishes or containers placed on the top rack can sometimes come into contact with the heating element during the drying cycle. This can cause the plastic to melt slightly and leave black marks on nearby dishes.
Overloading: Overloading the dishwasher can prevent water and detergent from reaching all the dishes effectively. As a result, some dishes may not be cleaned properly and may end up with black marks due to the accumulation of food debris.
Improper Loading: Incorrectly placing dishes in the dishwasher can lead to water or detergent not reaching certain areas, leaving them dirty and susceptible to developing black marks during subsequent wash cycles.
Detergent Residue: If you use too much dishwasher detergent or the detergent isn't suitable for your water hardness level, it might not rinse off properly during the wash cycle. The leftover detergent can then burn on the dishes during the drying phase, causing black marks.
Hard Water: In areas with hard water (water that contains high mineral content), mineral deposits can accumulate on dishes during the wash and dry cycles, leading to black marks and streaks.
To prevent black marks on your dishes, you can try the following:
- Ensure proper loading of dishes to allow water and detergent to reach all items effectively.
- Avoid placing plastic items near the heating element.
- Use the appropriate amount of dishwasher detergent according to the manufacturer's guidelines and your water hardness level.
- Check the dishwasher's heating element for damage or signs of corrosion and have it repaired or replaced if necessary.
- Consider using a dishwasher cleaner or descaler periodically to remove mineral deposits and other residues from the dishwasher.