If any of the liquor bottles in your bar are less than one-eighth full (like that 1989 creme de menthe), toss 'em. If there's more than a cocktail's worth, try out a new drink, such as a stinger or an Amaretto sour. But remember: "Some low-proof liqueurs can spoil, says Dale DeGroff, author of The Craft of the Cocktail (Clarkson Potter, $35, www.amazon.com). "Spirits of 80 proof will last for years in most cases, but liqueurs should be tasted if they have been stored for that long."
