Method #1

French horns are the only brass instruments today that still commonly use the rotary valve system. The valve is operated with a key attached to a string that rotates the valve in its casing to manipulate the air flow through it. Rotary valves need consistent maintenance and can cause lasting problems if neglected. If a valve becomes sticky, it is probably already too late. Because you play an instrument owned by Centennial Middle School, it is expected that you oil your valves every time before you play. Do not expect another student to do it for you.

Locate a bottle of Rotary Valve Oil either in your case, or in the container at the front of the bandroom for school-owned instruments. You will also need a Shop Rag. 1.
Remove the Valve Cap counter-clockwise. 2.
Fill the small reservoir with oil. 3.
Replace the cap counter-clockwise while the cap is upside down, paying close attention not to spill the reservoir. Turn the horn so that the valve cap faces up and work the oil into the valve by moving the key. 4.

Method #2

There may be conditions that require you to oil your valves quickly. This method will help you get back to playing your French Horn faster, but it will cause you greater problems if it is done improperly. Use caution in order that the oil does not slide down the inside of the tuning slides and drag dirt and grease with it into the valve.

Remove the slide(s) attached to the valve paying attention to press down the key and/or thumb key that it is attached to. 1.
Hold the instrument so that the open slide section's tubes face up, and drop oil down the slide directly onto the valve. Do not allow oil to drip down the sides of the slide. This is where the oil will drag dirt with it into the valve creating further difficulties. 2.
Replace the slide(s), pressing down the key(s) attached to it. If you do not press down the key(s) you will create pressure in the valve casing that may lock the valve up completely. 3.