When inspecting your furnace's ventilation system, there are several safety precautions that we should take. - Ensure the furnace is turned off and allow it to cool down before starting any inspection. - Wear protective gear such as gloves and goggles to safeguard against potential hazards. - Additionally, make sure the area around the furnace is clear of any flammable materials. - Lastly, if you're unsure or uncomfortable with inspecting the ventilation system yourself, it's best to contact a professional HVAC technician for assistance.