I generally leave my Bach Strad on its K&M stand, day and night, in the area where I do most of my practicing. A comfortable, climate-controlled room on the second floor. It's almost always uncased in open room air. During that time, I've noticed only slight areas of tarnish, which never get very far...I stay on top of these things and like to keep a clean, pretty horn. Anyway, I had to leave town for a few days; so I put the horn in its case and locked it up in my safe, as I did on one prior occasion this past February...for only two nights, I believe. Came home that time, got the horn, it looked fine; I uncased it and I put it back on the stand. When I opened the case this time, the horn didn't look at all like it did when I left it. When I retrieved the horn today I noticed a light yellowish cast or tinge all over it...almost like a very light brass. It was due for a complete cleaning anyway, so I attended first to the tarnish. I have Tarn-X, which I've used in the past, successfully, but never enjoyed the experience. This time I broke out my Denis Wick Silver Cleaning Cloth to remove most of the tarnish and followed up with a product I just bought called Wright's Silver Cream, which I found very easy to use, especially for getting into nooks and crannies. Then I just cleaned the whole horn thoroughly with water (which removed any remaining Silver Cream). There might be an easier way, and I'm open to suggestions, but it looks good as new, and tarnish removal isn't the point of this post. What I can't figure out is how it happened in the first place, so that I might avoid repeat episodes...possibly even worse. The safe is on the first floor, does not contain a dehumidifier (one could be added), but our AC is very efficient, the entire house is cool and dry through all seasons...if that even matters. I'm not wise in the ways of tarnish, but I was truly surprised to see the Strad go from shiny silver to dingy light yellow within no longer than 5 days. No harm done; everything cleaned up nicely, but I'm mystified as to the cause. Something about its environment clearly didn't agree with the finish. Again, it was secured in it's original case inside the safe. Any tarnish authorities out there with possible explanations?