The active component in Le Clef du Vin is a small disc embedded in its tip, composed of an amalgam of copper, gold and silver. Dip one second in a standard glass of wine, and it in effect ages the wine one year. This can help you two ways: to decide if a wine is worth investing in to store for the long haul, or to improve the taste of a very young wine.
Does it work? Yes and no. I first tried it on a bottle of Two Buck Chuck (Charles Shaw Merlot) and it had no perceptible effect even at 10 years/10 seconds. But a $15 bottle of 2012 Beaujolais Village noticeably improved. It became mellower and more enjoyable.
A 2009 New York Times article by food scientist Frank McGee suggests what is actually happening: the metals remove sulfites from the wine. Sulfur is associated with sharp, unpleasant tastes, and smells as well. That article reveals a couple of other tricks: you can remove the skunky properties of a wine that has reacted with a contaminated cork by pouring it into a bowl lined with plastic wrap. The plastic captures the molecule that is causing the cork contamination. And, if you want to accelerate the aging of a bottle so you can drink it sooner… store it on top of the refrigerator where it’s warm but not so hot it cooks the wine.
I also found a conversation on chowhound.com on Le Clef that became so vitriolic the hosts removed many of the posts and shut it down. What’s left is well worth a read both for the writing and for the opposing points of view.
The “travel” size of Le Clef du Vin sells for $50 on Amazon. It’s a stick shaped somewhat like a shoehorn, with an asymmetrical jog at the end, and comes with a plastic sleeve so you can slip it into a purse or lapel pocket. I highly recommend it as a gift for the oenophile who has everything, if only for the entertainment value and possible fisticuffs that might ensue.