I have just bought a new copper trombone mouthpiece and it left a black residue on my lips after using for the first time. Does anyone know what this could be?

  • 1
    Does it still happen after washing the mouthpiece?
    – Aaron
    Commented Jun 5, 2023 at 16:36
  • Don't take it the wrong way, but did you have traces of food in the mouth? Even coffee breath could cause fresh clean copper to start reacting. Energetic foods like garlic and curry could accelerate the oxidisation of copper, which generally goes copper->reddish->black->light-green.
    – Criggie
    Commented Jun 6, 2023 at 0:50
  • Is it a new trombone also? I believe they fill the outer slide tubes with fine ballast powder so they don't crimp when being bent into shape. On my trombone it took several weeks to stop seeing the powder
    – nuggethead
    Commented Jun 6, 2023 at 10:33
  • Copper oxide is black, but I'd be surprised if that would be created so fast.
    – U. Windl
    Commented Jun 6, 2023 at 13:34

2 Answers 2


Plain copper (i.e. without any surface plating) is an uncommon material for a brass instrument mouthpiece. Maybe it's a very expensive boutique mouthpiece. Or (if it's new to you rather than new from a shop) maybe it used to be plated and someone has polished it too vigorously?

The black will be the copper reacting with skin around your lips. Probably not hazardous, but not a good look.

You could investigate getting it silver (or gold!) plated, or (much cheaper) paint some clear nail varnish around the rim to stop the bare metal touching skin.

  • I wonder if it's actually copper and not brass? Brass is far more common, and might be mistaken for copper. (It is of course a copper/zinc alloy, and some brass has more copper than other brass). Though I think stainless steel is the most common, even if the rest of the instrument is brass. I've also heard of titanium being used, but steel and titanium obviously would not look like copper. Commented Jun 6, 2023 at 13:24
  • Nearly every mouthpiece is machined brass which is then silver or gold plated. Stainless steel and titanium are very much harder to machine than brass, so mouthpieces made from them are uncommon. Commented Jun 6, 2023 at 21:06

Upon further review it appears that it might have been grease left over from the factory polishing the mouth piece.

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