I had an opportunity to sample some Scotch (cant remember name) that had been given as a gift in 1945. This bottle was less than half full and had been sitting upright on a shelf for 60 or more years. The cork was brittle and falling apart. The Scotch was like nothing that I ever drank before. I dont mean this in a good way. The aroma reminded me of a can of turpentine in which paint brushes dipped in varnish had been cleaned. Nasty is the only word I can think of. I had some Bell's Scotch circa 1970 that had been treated the same way...except the bottle had never been opened. This was 40 year old Scotch and was quite pleasant. Clearly air in the older bottle didnt do the Scotch any favors.