Vetter windows

Wow we've had Vetter windows for 10+ years and they are great!!! One time I noticed moisture on some of them and I knew I better do something about it right away. I called around and someone asked me if I had turned up the humidifier on the furnace, and I had done that. They said to adjust it and I did that and never had a problem with them since. I read the comment about closing shutters keeping the moisture in and I think they are on to something. Our house is full of the Vetter windows but I have very few curtains, shutters, etc. on them. We have a western view onto a lake and get a lot of wind, rain, sun from that direction but we like the open view. I just need to find a crank handle and the plastic cover for it. Any help on that?