How do you clean a trombone and care for the slide?

Why the slide is the most delicate part

The slide consists of two pairs of tubes: the fixed inner tubes and the outer tubes that slide over them. There’s very little clearance between them, and contact is concentrated at the lower ends of the inner tubes, which are slightly wider. That’s why any deformation, even one you can’t see, creates a point of friction.

A trombone falling on its side, a slide hitting a music stand, or a case crushed in a car trunk can leave the slide stiff until a technician repairs it. Three habits help protect it:

• Keep the slide lock engaged whenever you aren’t playing.
• Hold the outer slide by its cross brace, never by squeezing the tubes.
• During breaks, use a trombone stand or put it in its case; never rest it on a chair or lean it against a wall.

How to lubricate the slide: cream, water, or spray

There are two main systems. Both work; what matters is using only one, in small amounts.

1. Hold the trombone by the inner slide’s cross brace, disengage the lock, and slowly slide off the outer slide.
2. Wipe the inner tubes with a cloth to remove the old lubricant.
3. Apply a small amount of cream only to the lower end of each inner tube.
4. Replace the outer slide and move it through its full range to spread the cream.
5. Mist the inner tubes with water and move the slide again: it should feel light.

If the slide slows down during rehearsal, a mist of water is usually enough; you don’t need more cream. Too much cream is a common mistake: it builds up, traps dust, and makes the slide heavier. Never use petroleum jelly, household oils, valve oil, or spray lubricants, and never mix cream with liquid lubricant: together, they form a paste that slows the slide.

Cleaning inside the slide

If you play daily, clean inside the outer slide every three or four weeks using a long trombone cleaning rod and a strip of gauze or thin fabric.

1. Separate the outer slide from the rest of the trombone.
2. Wrap the gauze spirally around the rod, covering the tip completely so the metal can’t touch the tube.
3. Gently insert the rod into one tube, holding the slide by the cross brace, and stop before the bend at the end: hitting it will dent it.
4. Repeat in the other tube, replacing the gauze if it comes out very dirty.
5. Wipe the inner tubes with a clean cloth, reassemble the slide, and lubricate it.

You can also wash the slide with lukewarm water, mild soap, and a flexible brush, taking care around the bend. Dry it thoroughly before lubricating.

The bell and tuning slide

Wash the bell section like other brass instruments: lukewarm water, mild soap, a flexible brush, rinsing and drying; the full procedure is in how to clean a trumpet. Use tuning-slide grease on the tuning slide, not hand-slide cream. If your trombone has a rotary valve, do not dismantle it: apply rotor oil where your teacher or technician indicates.

Mouthpiece and water key

The mouthpiece

Wash it once a week with lukewarm water, mild soap, and a mouthpiece brush. Store it in its compartment and don’t drop it: the shank can deform and no longer fit the receiver. If it gets stuck, see a technician; pliers mark the mouthpiece and can damage the receiver.

The water key

It’s on the bend of the outer slide. To drain it, extend the slide a little, press the key, and blow without buzzing your lips. Do this whenever you hear a gurgle, not just at the end.

The key seals with a small cork or rubber pad that wears out over time. If air leaks through it, the trombone sounds dull and low notes become harder. Check that it closes properly and that the spring is strong; replacing the cork is a simple repair.

Assembling and disassembling safely

1. Remove the slide from the case by its cross braces and check that the lock is engaged.
2. Hold the bell section by the brace or the sturdiest tube, never by the rim.
3. Join the two sections at an angle, roughly a right angle or whatever feels comfortable, and tighten the nut by hand without forcing it.
4. Insert the mouthpiece with a gentle twist.
5. To disassemble, reverse the order and store the slide with the lock engaged.

The most common accident happens during assembly: the lock is disengaged, the outer slide slips off, falls to the floor, and dents at the bend. That’s why you should check the lock before moving any part.

Transport: buses, cars, and bands

• On a bus or TransMilenio, keep the case upright and close to you, and don’t let anyone lean or sit on it.
• In the car, put the case on top of everything, never under luggage or groceries.
• Don’t leave it in a trunk in the sun: heat softens the cream and grease.
• A hard case protects the slide better than a soft bag; if you use a bag, choose one with firm padding around the slide.
• Check latches and hinges occasionally: a case that opens while you’re carrying it is a quick way to dent a trombone.

In parades and school bands, trombones spend hours in the sun and travel on crowded buses. If that applies to you, read how to get started in a wind band and always keep a water spray bottle and cloth in your case.

Mistakes that damage the slide

• Applying cream along the full length of the inner tubes.
• Mixing cream and liquid lubricant, or changing products without cleaning first.
• Trying to straighten a dent at home.
• Hitting the slide’s bend with the cleaning rod.
• Storing the instrument in its case with the mouthpiece attached.

In trombone lessons, your teacher checks the slide with you from the first few weeks. If you don’t have an instrument yet, our guide to choosing your first trombone explains what to check on the slide before buying.

Frequently asked questions