"Junk," Gordon McKinney said, as he fussed with some tarnished beer coasters. "I sell junk. Any kind of junk, all kinds of junk. And make sure you spell it right: j-u-n-q-u-e."

Few of the more than 400 dealers at The World's Fair of Collectibles, which opens today at the D.C. Convention Center, are as blunt as McKinney, but the aisle after aisle of campaign buttons, postcards, movie posters and tired fur stoles looks like the ultimate yard sale. But look at the price tags! The sad-looking teddy bear sells for $75, the rusting Coke machine is more, the oil painting of the anonymous GI in front of the Statue of Liberty is $450.

A collectible need not be antique. It doesn't even have to be old. The most serious dealers will say it has to be unique, but a few whisper with a trace of embarrassment that a collectible is anything someone is crazy enough to buy.

"Everyone has something good he remembers from his childhood," McKinney said. "Jack Armstrong stuff, maybe. So they start collecting that and go from there. Some collect beer bottles, the brand they drank when they were young. Some collect razor blades. Anything."

That same nostalgia motivates the dealers as well. Many of them began with their own small collections only to find that the postcards or velvet hats had overflowed their closets.

Elliot and Rosemary Sherman of Amherst, Mass., got involved in collectibles when they decided to get rid of some stuff lying around the house. "We went to a flea market and made a whole lot of money," Rosemary Sherman said. "That was 10 years ago, and now it's how we make our living. We like it because it lets you touch a little bit of history."

Even before the doors opened to the public, the dealers were working. Bob Curry of Pittsburgh sold 10,000 postcards to other dealers in the first day. "When the public comes through, you two-dollar them to death. You make your biggest single sales before they even get here."

The World's Fair organizers, Mary and Hubert Bellman, claim this is the largest convention of toy, doll and games dealers in the country, with participants from across the United States and Europe. This is the first year they have called it "world's fair" and moved it to Washington from Gaithersburg.

Despite its name, only a third of the show is collectibles. Most of the dealers sell dolls, many of them antique.

Doll dealer Charles Farrow came over from London just for the fair. "The antique doll business is an international one," he said, pouring more champagne into a plastic Howard Johnson's cup. "The interest in dolls has been rising since the war. The U.S. got it going, but now I send out dolls to collectors in Australia, South Africa, South America. Of course, the field is increasingly popular for copyists, forgers. They take old wood, old cloth, and make very good copies of the most valuable dolls, like this 18th-century Queen Anne doll, which sells for just under $3,000. I am sure that there are dolls in many Queen Anne collections that have only been dolls for 10 years, if you know what I mean."

The show is open from 10 a.m. to 6 p.m. today and noon to 4 p.m. tomorrow. Admission is $3.