Hello! I live at the beach and played my king 2B on the boardwalk yesterday. After my routine cleaning I noticed some turquoise looking spots along the pinch of the bell.

Could this be corrosion from the salty air?

Would love to hear your thoughts and recommendations :)

https://drive.google.com/drive/folders/1-1_HnxuCvYZOIKdGvosZzYI3KtqSi8Bo

Sounds like typical acid bleed.

Um, no. Acid bleeds are usually brown. Turquoise spots are patina caused by salt air. Dip a cloth in some vinegar and wipe or rub the turquoise spots until they go away, then rinse with another cloth dipped in plain water and a couple of drops of dish soap, like Dawn. Wipe dry.

Probably caused/aggravated by water draining out of the slide and on the bell in the case. Take a look at your case set up…….are the open ends of the slide stored at the same end as the bell rim?

I think it might be from the salty air affecting the exposed brass because it did rain a bit. The trombone is is 50+ years old and it's a beautiful mess of colors and textures.

I started w/ the cleaning method baBposaune suggested with the vinegar, but when I got around to the dish soap I immediately noticed some yellow on my cloth, which isn't a good sign so I had to stop and dry it off.

The white/turquoise spots remain.

There is a separate panel in the case so the slide doesn't make contact with the bell, plus I clean/dry the slide after each session so it can't be from the slide.

That looks like oxidation of the areas where the lacquer has flaked on the edge of the bell due to wear, with some also occurring where the lacquer has flaked due to acid bleed. I would just wash the horn to get all the salt off, and rub a bit of lanolin onto the areas, which can help it form a nice patina.

[quote="andrewmorales93"]There is a separate panel in the case so the slide doesn't make contact with the bell, plus I clean/dry the slide after each session so it can't be from the slide.[/quote]

The slide doesn’t need to make contact with bell in the least bit. The slide can be in a different compartment and cause major damage to the bell. Also….you can swab your slide after every playing and moisture can still be in there and condensate into droplets.

Which side of the slide is in the case beside the bell rim? Is it the water key end or the mouthpiece end?

If the mouthpiece/bell tenon end is down by the bell rim, water is probably draining on the bell rim area every time you put it in the case. This is common in numerous trombone cases. The old French-style Bach cases were notorious for this. I think about 98% of all Bachs that had that style case (even if the slide was swabbed and never touched the bell) eventually got corrosion around the rim because water drained from the slide and settled on the rim of the bell.