Automotive bulb grease protects bulbs from moisture and corrosion, but is often not applied correctly. This video discusses the properties of bulb grease (also known as dielectric grease) and what it does to protect bulbs. Sealing headlight assemblies and taillight sockets, bulb grease can do it all! Pretty much anywhere there is a seal for an automotive bulb, carefully applied bulb grease can add life span to lighting and components! Cars Simplified: Everything Automotive Explained video.