How do you bleed a radiator to remove trapped air and improve its efficiency?

To bleed a radiator, you need to locate the bleed valve usually found at the top of the radiator. Use a radiator key or a flathead screwdriver to slowly open the valve until you hear a hissing sound. This will release any trapped air in the radiator. Once water starts to come out, close the valve. This process helps improve the radiator's efficiency by allowing hot water to flow freely through the system.