Hi. I found this website and thought i would see if anyone knew the answer to my question. My question is, There is a white build up inside the two trill keys (the two keys close together located below the second octave key in the top joint), can anyone tell me what it is? Is it from the age of the oboe? Is it mold?

The oboe is a 1971 Rigoutat Classic.

Thank you in advance.