There's a straightforward solution to this question: reusing corks may harm your wine. Corks can harbor molds that, when exposed to chlorine molecules, produce the unpleasant, swampy "corked" fragrance of 2,4,6-tricholoranisole. Corks can also leak, enabling wine to escape or allowing air to enter. This can lead to oxidation and aging of the wine. However, there is some evidence that using corks that have been sterilized by heating them for 10 minutes in a microwave oven can avoid this problem. Of course, you can't reuse any corks that have been used to bottle vinegar or other acids. The best option is to buy new corks to ensure that you don't contaminate your wines with mold or bacteria. If you can't afford new corks, then it's acceptable to use recycled corks so long as they haven't been used for acid-based beverages like vinegar or citric juices. However, even if you follow all of the instructions on the corks box, some contamination is inevitable. So the next time you open a bottle of wine, be sure to drink it before it gets too old.