metal - Brass Instrument: Dezincification or just scrubbed off?

I do own a brass instrument (a trombone). The lacquer is damaged. I asked how to deal with it here.

Now I learned that the brass contains zinc, and there is a corrosion process called "dezincification". Now they told me to ask here how to identify real dezincificated parts. Here are the pictures:

Main slide handle:

Bell "middle" section:

Bell inner rim:

The issue is: On trombones (other brass instruments) red rot (dezincification) usually only appears on parts where saliva touches the instrument, i.e. in the front parts. On a trombone that would be the slide. So it is kind of unlikely but not unheard of that this might be "red rot" or dezincified.

It might also just be lacquer which went off due to improper handling (like not cleaning water spots, showering/cleaning the trombone with way too hot water, etc.).

Actual questions

• How do I identify dezincifiaction correctly? Can it be seen on those pictures? (most important question)


• What do you think of chemical cleaning? It sounds dangerous to me. Isn’t it going to damage the instrument?


• What do you think of cleaning such an instrument soap? Is this going to damage the lacquer or material?