To keep your trombone in the best condition, please follow these suggestions:

Assembly

Always consult your teacher if you are not sure how to put together your instrument.
NEVER force the parts of your instrument together.
Always lock the slide when you are assembling or not playing your instrument.
Assemble your trombone so the bell is over your left shoulder. With their teacher’s close supervision, young children should make sure that the hand slide is a comfortable distance from the bell brace for the left hand position.
Make sure that you tighten the bell to hand slide fastening nut until it is snug and secure without over tightening.

Hand-Slide Oil Application

Always consult your teacher if you are not sure how to apply hand-slide oil.
You should apply hand-slide oil to your instrument at least once a week. To apply, put the hand slide in approximately third position and apply a generous amount of oil to each slide. Your teacher can instruct you on how to determine the amount of oil that is needed.

Tuning Slide Grease Application

Always consult your teacher if you are not sure how to apply tuning slide grease.
You should grease your slide as needed according to your teacher’s instruction.
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 trombone.
A properly set tuning slide will slide in just by pushing on the outer edge of the crook. If you need to manipulate the slide to push it in it should be repaired.

Maintenance

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 move and grease the tuning slide at least once a month and oil the hand slide at least once a week (or more frequently if needed). DO NOT ATTEMPT TO REMOVE THE MOUTHPIECE OR SLIDES IF THEY BECOME STUCK. A lack of oil and grease will cause the parts of your trombone to stick. If they do stick take it to a technician immediately for removal. NEVER try to remove stuck parts with pliers or hammers!
Wipe off your fingerprints from your trombone after every use. A clean, non-treated cotton cloth will work the best. If you do choose to use a treated polishing cloth be sure that it is for the proper finish. Using the wrong cloth could cause scratches.
Always store your instrument in its case with the lid closed when not in use. This will prevent any excess tarnishing and lower the risk of damage.
Do not put anything (including sheet music) inside the case with your instrument that does not belong. Closing the case with extra contents can cause damage to the valves or dents. Also, make sure that all the latches are securely closed before transporting your instrument.