Always consult your teacher if you are not sure how to apply valve oil to your trumpet valves.
The purpose of valve oil is to clean, lubricate and fill the air space inside the trumpet valves. You should oil the trumpet valves before each time you play, preferably without completely removing the trumpet valves. This will prevent accidental damage to the trumpet pistons.
Remove the top cap and pull out the piston far enough to see the valve and apply enough oil to fully cover the surface. (Do not oil the valves from the bottom caps) Using too little oil will not properly lubricate your valves. Using too much oil will not cause any damage to the trumpet.
Replace the valve without excessive rotation. As you lower the valve, slowly turn it clockwise until it locks into place. The oil will naturally distribute itself when the valves are depressed.
Confirm that the valve has been replaced properly by blowing through the instrument. You will also need to apply oil to the small water key about once a month.
Your mouthpiece should not have any dents in the end of the shank. If you notice any dents in your mouthpiece you should immediately take it to a technician for repair. You should grease your slide at least once a month. You should move and grease all slides and bottom caps at least once a month. When bottom caps are removed you can apply a small amount of slide grease to the threads of the cap for easy turning. If the bottom caps are dirty you can wash them in warm water and let dry completely before greasing and reassembling.
Slide Grease Application
Always consult your teacher if you are not sure how to apply slide grease. You should grease your slide at least once a month. Remove slide and wipe off the old grease. Apply a bit of grease to one end of one of the slide tubes and re-insert this side. Gently rotate the slide as it is pushed in, evenly distributing the grease to all parts of the slide. Repeat this process with the other end of the slide tube. When completed, insert the slide as normal and remove all excess grease. NEVER use Vaseline in place of slide grease. This will corrode your trumpet.