Valve oil

Valve oil is a lubricant for valves of brass instruments. It is typically mostly mineral oil with a small amount of other ingredients, although synthetic oils are increasingly available. Valve oil is a lubricant for valves of brass instruments. It is typically mostly mineral oil with a small amount of other ingredients, although synthetic oils are increasingly available. Besides lubricating the moving parts of the valve, valve oil provides corrosion protection to the bare metal of the inner valve. While the valve piston or rotor is made of a metal which is more resistant to corrosion, the inner valve casing is typically bare brass. (The brass on the outside of a modern instrument is lacquered or plated to prevent corrosion.) The oil also completes the seal between the valve casing and the piston or rotor.