An open gas flame.
A hot burner.
A heating element.
Hot oil or grease.
What Should Never Go in a Dishwasher
Some household items are better washed by hand, including:
Delicate glassware.
Sharp knives.
Wooden cutting boards and utensils.
Cast-iron cookware.
Some plastic containers.
Non-stick pans, depending on the manufacturer’s instructions.
These items can become damaged or damage the dishwasher over time.