'Psst! Wanna buy a piece of the Brooklyn Bridge?'

So you've always wanted to buy the Brooklyn Bridge? Well, here's your chance -- at least to buy a part of it. No, this isn't a reprise of the hoary tale of the naive newcomer buying the famous suspencion bridge from a "con artist."

All the details are contained in a glossy, colorful new booklet just published by the city's Office of Real Estate Development and entitled "How New York City is selling the Brooklyn Bridge. . . ."

But in a recent interview, Mayor Edward I. Kock disclosed that the city is only "selling parts of it" -- specifically, the "vaults," or storage areas, under the bridge.

Then asked if he intended selling old subway cars, too, the major said with a sly smile: "I hadn't thought of that. That's a good idea."

Actually, selling the Brooklyn Bridge vaults is symbolic of New York's campaign to market long-forgotten city-owned real estate to bolster revenue.Currently there are more than 15,000 commercial and industrial parcels available for sale or lease.

Want to buy an old schoolhouse, a five-story limestone former police headquarters building, or even your very own island in the East River? Go no farther -- Mr. Koch is your man.

The old police headquarters building, in the heart of Manhattan's colorful Little Italy section, even has official landmark status. It's vintage 1909.

The island in the East River is North Brothers Island, and comes complete with a crumbling hospital complex which could be removed to make room for beautifully landscaped waterside apartments or condominiums. Of course, getting there would pose a slight problem. There are no bridges or causeways to it. And then, North Brothers Island is near Rikers Island, home of a mammoth state penitentiary.

Dubbed the "First Annual New York City Marketplace," the sale and lease of all this out-of-the-ordinary property will be held on Dec. 1 and 2.

A promotional package on the properties quotes Mayor Koch: "The properties featured in the insert booklet represent the exciting potential for economic reuse of city-owed property."

But before you buy the Brooklyn Bridge vaults, you'd best have some idea what to do with them. The major, himself, says he's thought of buying them, but "they are just to big."

Altogether, some 18 separate storage areas underneath the land portions of the bridge are available. It's unlikely they could be converted to residential use as could some of the other properties. But, then, a lot of unlikely things are done in New York City.