Dropping a penny into wine that tastes gross sounds like a bad idea. After all, throwing good money after bad is generally a dangerous game. But when the bad money is skunky wine and the good money is a single, well-washed penny, I'm all for it.
Here's why it works: These sulfur-y smells usually come from a chemical process called reduction. Reduction can produce stinky sulfur molecules called thiols. But luckily, copper reacts with these molecules to create copper sulfide crystals -- which are blessedly odorless.
Old pennies work best, since those minted before 1982 are made almost entirely of copper. But new pennies, which are made of zinc and plated with a copper coating, will probably do the trick in a pinch.