A few years ago, Greg Gilbert an information systems manager in Virginia, was poking around the shelves at the back of a Washington, D.C. liquor store, looking for rare whiskies. Suddenly, his eyes lit up. He struck gold. No, he didn’t find a 23-year-old Pappy Van Winkle. It was a faded, dust-covered bottle of six-year-old Old Forester Bourbon, bottled in 1971. The price: $11.95.

Gilbert hunts for dusties—American whiskey brands, often long forgotten, that have sat in stores for years. Like Gilbert’s bottle of Old Forester, they’re usually among the cheapest booze on the shelf. But dusty-hunting isn’t about value—it’s about drinking a tasty piece of whiskey history.

Finding these treasures is still possible—for now at least—because of overproduction in the 1950s and 1960s. As fans of Mad Men well know, there was a time when Americans loved brown spirits, and distillers ramped up their case counts in response. But in the 1970s, the bottom fell out, as consumers switched to “lighter” drinks like vodka and white rum.

Since whiskey doesn’t change very much once it’s capped, the bottles simply stayed on the shelf collecting dust. So today, in out-of-the-way liquor stores—as well as grandparents’ liquor cabinets, or the basements of old taverns—seekers like Gilbert can still find some of the best whiskey ever produced.

Part of the appeal is history, says David Driscoll, a spirits buyer for K&L Wine Merchants in California, but more importantly, it’s the unique flavors these abandoned bottles can hold.

“Today, we have computers, automation and our understanding of the science of making whiskey is light years ahead of where it was,” says Jamie Boudreau, the owner of Canon, a Seattle whiskey bar that serves time-capsule cocktails so you can try, say, what a Rittenhouse Rye Manhattan tasted like in 1968.

But that precision in production often came at the cost of the hand-hewn character that defined American whiskey, says Boudreau. Before industry consolidation and automation in 1980s and 1990s, distilleries were relatively small and frequently tinkered with recipes, creating flavors that were often deliciously inconsistent and nuanced from one batch to the next.

“It was still so much an art form, very hands on,” says Jared Hyman, the manager of Bourbon Glover Park, a whiskey bar in Washington, D.C. “The taste of a lot of these old whiskeys is often far superior to what is being put out today by the bigger guys.”

At a time when the prices for some coveted, premium American Bourbons, like Pappy Van Winkle, are climbing into the four-digit range, it’s refreshing that anyone can walk into a liquor store and find a truly rare—and great tasting whiskey—at a fraction of the cost.

“While hunting, I can hit a dozen or more stores before finding the one that has some gems,” says Gilbert. “When that happens, a small smile crosses my lips.”

Dusty Hunting Tips

The Tax Strip

Before tamper-resistant plastic seals and caps became common in the 1990s, distillers placed strips of tape over the tops of their bottles to prove they hadn’t been opened—more to satisfy tax inspectors than to protect consumers.

Long-Lost Producers

Anything made by distilleries that have ceased production, like National Distillers or Stitzel-Weller—or, going way back, Schenley—is worth buying just for the historic value (though many of them made great whiskey, too).

Metric vs. Standard?

American liquor bottles used to be sized according to English measurements. Since 1979, they’ve been measured using the metric system—so anything in pints, quarts or gallons is a surefire dusty bottle.

Labels to Look For

1. Old Fitzgerald Bottled in Bond Bourbon (made by Stitzel-Weller)

2. Old Overholt Rye from before 1987

3. Jack Daniel’s 90-proof Tennessee Whiskey

4. Maker’s Mark 100-proof Bourbon

5. Eagle Rare 10-year-old, 101-proof Bourbon