How can I preserve my decorative cork stoppers when they're not being used?

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Dear Dr. Vinny,
I have decorative Christmas-themed cork bottle stoppers. How do I keep the corks moist all year when not in a bottle?
—Jean M., Hollywood, Calif.
Dear Jean,
Friends have given me decorative cork stoppers over the years and, unfortunately, once a cork dries out, it doesn’t rehydrate. I’ve heard of some people trying to soak or boil corks, but one of cork’s qualities is that it is waterproof, so it’s unlikely that either of these things will make a difference. Once it dries out, cork cells break down and cannot be revived.
If you’re having trouble fitting a cork stopper into a bottle, you can apply a thin coating of mineral oil or a food grade wax on the outside, which might help.
—Dr. Vinny