[Sax&Caps]

Pictured, how do I clean this bit off, I was cleaning and polishing my mouthpiece with warm water, a toothbruh, a mouthpiece brush, and dish soap and saw this little bit that I can’t get off. Should I just let it soak for a bit, or should I use something else.

 

[Guto]

the thin plating is just worn in this area. there isn't much to do about it really. as you use your mouthpiece more of its plating will wear out with time. an attempt to making this area more shiny would only aggravate the local wear.

I don't know the history of this mouthpiece but my guess would be that someone had the habit of leaving the reed installed on it after playing and the moisture in this area slowly corroded the plating.

 

[wanderso]

My supermarket cleaning products section sells silver-polish-impregnated non-woven wipes in a pull-out plastic tub that are gentle and may be used on any metal. If that were my mouthpiece, I'd try a gentle rub on part of the discolored area and see what happened.

My guess is that it is oxidation/tarnish that will clean right off with minimal effort, but you may have bare brass (now shiny) in that spot. But maybe there will be remaining plating.

Then wash with dish soap and water and you are good to go.

 

[Dr G]

the thin plating is just worn in this area. there isn't much to do about it really. as you use your mouthpiece more of its plating will wear out with time. an attempt to making this area more shiny would only aggravate the local wear.

I don't know the history of this mouthpiece but my guess would be that someone had the habit of leaving the reed installed on it after playing and the moisture in this area slowly corroded the plating.

+1 to “pitting corrosion” and its cause.