Pressure Cooker Lids
While a pressure cooker pot may go through a dishwasher cycle just fine, you should never put the pressure cooker lid in the dishwasher.
The lid contains the valves that control how well the cooker works. The action of a dishwasher can force small particles of food into the valves and vents and cause the cooker to malfunction (explode). The harsh chemicals can also damage the rubber or silicone seals of the lid.
Comment: Not guilty. I'm actually afraid of pressure cookers.