The single bottle of Puligny-Montrachet Clavoillon 1979, Domaine Leflaive, was bought soon after release and stored properly since. Domaine Leflaive had a very good reputation in the 70s, but this wine would not be expected to be of the class of their Chevalier-Montrachet from better years. However I found the level 3 in. below the cork, so I was expecting to have to discard the wine. However closer inspection showed the wine was clear and not dark. Also there was no evidence of leakage around the cork. There was a very narrow groove on the outside of the cork. Apparently this was enough to allow very slow evaporation over many years, but it was too small to allow gross leakage of liquid. To my great surprise, the wine was very good. It had a lemon color, no brown, and was very clear. It still had good fruit, the right balance of acidity, and high extract. The finish was very long. In fact it was far better than many wines from more famous vineyards of the era. Since I only bought 1 bottle, I can not compare with a bottle that has no issues.
Somewhat OT: Just as I was about to send this post, the doorbell rang, and I received the most difficult-to-find wine I have ever sought. I now have a bottle of Szepsy Tokaji Essenzia 1999. It contains only 2% alcohol because of the very high sugar content. It was at a wine firm in France. I earlier located a bottle in Poland, but the store did not ship.