My tuning slides were so badly stuck that I could barely move them, so one day I went to the drug store and purchased a can of Brasso metal polish.
Most brass players know that polishing an instrument with Brasso is not a good idea, because it strips the lacquer off and ruins the finish. Even aging instruments with worn off lacquer, or instruments that have had the lacquer stripped off for sound production purposes, should use it sparingly, because each time you polish a tiny layer of metal is removed from the horn.
Fortunately, you can use this property to your advantage. Find a soft cloth or rag (an old cotton T-shirt does the job nicely), and apply some polish to the unlacquered part of your tuning slides. Rub vigorously until most of the corrosion comes off. Follow the instructions on the can to give a final polish with a clean, dry part of the rag. Apply some tuning slide grease to the slides. They should be much easier to move now!
A Word of Caution
Brasso is a noxious substance that exudes toxic-smelling odors, and it is harmful or fatal if swallowed. It is wise to wear safety glasses, gloves, and use it in a well-ventilated area. Read the can for first aid treatment information.
Brasso should only be applied to unlacquered surfaces. Be careful not to get any on the lacquered, shiny parts of your instrument.
Wash your hands thoroughly after polishing with Brasso.
Don't polish too vigorously, as it is possible to take too much metal off. If this happens, you may need to use a thicker slide grease (e.g. lanolin) to prevent unwanted movement of your slide.
Brasso Material Safety Data Sheet (html)
Brasso Material Safety Data Sheet (pdf)
Marcus Hissen was born in Euskirchen, Germany and grew up on Vancouver Island. A member of the Victoria Symphony since 2004, he contributes passionately to the Symphony's outreach and education programs. In 2006, Marcus founded Music Corner, a musical storytelling quartet for young children. Marcus also performs school concerts as a member of the low brass ensemble "Heavy Metal."