Every once in a while I clean the end of my tenor neck (the end that fits into the body tube) with my shirt, a rag, whatever is handy to facilitate a smoother fit into the body. I suppose it cleans off "gunk". Last week I picked up a silk cloth that I use to pull through the body to remove moisture from the horn. The cloth was dry at the time. I cleaned the neck and inserted it into the body. After I finished playing I tried to remove the neck from the horn. No way. The neck was almost completely stuck. It would turn just a bit, but would not pull out of the horn. I tried heating the body/cooling the neck, slowly working the neck back and forth for quite a while. Finally I got the neck out and found a greenish white powder all over the brass. Clearly, some sort of chemical reaction had happened, but what? I cleaned the body and neck with a clean cotton cloth and reinserted the neck. Smooth and silky...great fit and no binding. So, techie types...what happened? Was it the silk rag? The residue of old saliva on the silk rag? Acid in the saliva? What would cause brass to react that way?
Inquiring minds want to know.