When performing an engine preheat before removing refrigerant what should be done?

Before removing refrigerant, the engine should be preheated to ensure the refrigerant is at the correct temperature for efficient recovery. This helps reduce the viscosity of the refrigerant, allowing for more effective evacuation from the system. Additionally, ensure that the system is off and that proper safety precautions are taken, including wearing appropriate personal protective equipment. Always follow manufacturer guidelines and local regulations regarding refrigerant handling.