Hello,
I have a wooden Lachenal and had not played for a couple weeks. When I opened my case today, I saw some mold in the wooden ends and on the straps. I didn't notice it immediately, but still it was more than just a small amount. I used an old, soft bristle toothbrush to try to clean off as much of the mold as I could. I used a paper towel to wipe away the rest. I'm reluctant to use any alcohol cleaning solutions as the ends are wooden, and it's an old instrument.
My apartment has extreme climate fluctuations during the year: in the winter it's bone dry and I need to run a humidifier when I play and keep a small humidifier in the case; in the summer it's usually over 80 degrees with high humidity (average is 60%). We will run the AC in one room when it's very hot, but I usually don't keep the concertina in there. Any advice is welcome on cleaning; storage; and how to prevent this from happening in the future. Thank you in advance.