Nothing is more in style than vintage clothing that went out of style years ago. It is not only the cut of the clothes but the cut-rate prices for high quality garments that have caused a boom in "old" clothing in Washington and elsewhere.

To meet the growing demand, many vintage clothing stores have opened here in the last year or so including Geraldine's (4015 Wisconsin Ave.). Second Hand Rose (1516 Wisconsin Ave.). Repeat Performance Resale Shop (Rockville) and Twice but Nice (Gaitherburg). Sophisticated boutiques like Exit in Georgetown have brought in old things to sell along with the new. "The tailoring and the bias cuts are so grea' I cant't resits," says Anne Bradshaw, owner of Exit. "Besides the clothes are soft while the new clothes have a hardness to them."

But the heart of the old clothing business locally is a three-story ware house full of used clothes housed in a pre-Civil War slaughterhouse in Northeast Washington. Called Classic Clothing (3701 Benning Rd. Ne), it sells wholesale to stores all over the world as well as to individual customers here.

"I was in Paris and saw these bowling shirts.We were selling them for $3 but in Paris they were selling like mad for $20, says Brian Streidel, 24, who was two credit courses away from an accounting degree when he dropped out to find customers in Europe, particularly France, England and Holland, for the used clothing for his family's business.

Second-hand clothing has always been the cheapest way to acquire things to wear. Since the late 1960s, used clothing stores that traditionally catered to the poor became the hunting ground for others, particularly the young, looking for something nostalgic, even funky to wear. The price tag was the clincher.

Today, shopping the second-hand stores is a way of life for many seeking a way to cope with increasing clothing costs as well as adding individuality to their current wardrobe. The quality of workmanship in many of the earlier styles, the use of natural fiber fabries, particularly silk and wool, and the uniqueness of the styling, are the bonuses for those willing to scout the market.

"Old clothes have a special sense of style, and far more indiciduality then clothes mass produced today," says Joan Danziger, a sculptress. "It's a collectire way of dressing, like a contemporary house with old furniture."

In New York this summer, crepe de chine-like print dresses from vintage clothing shops where the hot weather uniforms forsome of the best-dressed young women who never bothered to have them altered to fit perfectly but wore them loose and oversized, often pulled in a the waist with a narrow belt.

The sport of recycling old ilothes, as will as the necessity, has boosted the number of classes in clothing alterationsin Washington and inspired several new books, among them Gloria Mosesson's "New Clothes from Old" (Bobbs Merrill.)

"I've been wearing old clothes for five or six years," says Richard Mosro, manager of Nathan's I and II. "I like them better and I don't end up loking like everyone else. Most of the new clothes don't excite me like the old ones do, particularly the trousers and bow ties."

Brian Streidel's parents started in the used clothing business in the 1950s with a tetail store. Like-Nu Clothing on 7th Street and an export business, sending cheap used clothing to India the Phillipines and Hong Kong for resale.They closed the store after the disruptions that came with the Martin Luther King assassination and focused on their wholesale business at the North-east warehouse.

Streidel found in Paris that the "kids wanted the unconventional items like Boy Scout shirts. Army uniforms, vests printed dresses, bowling shirts and university sweater," he says. Now he bales these up, 250 at a clip, and ships them to shops all over this country and abroad.

When Streidel talks about Classic Clothing as the rag business, it isn't just trade lingo. Bundles of clothing are purchased by the company's agents and shipped to them in crates, bins, bales and barrels. It is sorted by quality, the best of it cleaned, pressed, repaired, scaled down to a typical size and sold as nostalgic gear.What is unwearable because of rips and tears is turned into rags and sold to institutions for wiping cloths.

The warehouse itself is divided by quality of clothes. On the top floor are theunsorted items in barrels, boxes and bins - what Streidel calls the "treasure hunt" area, and few things have a price tag over $10. The second floor holds racks of vests, pleated trousers, dresses, bowling shirts, bomber jackets, sweaters and the like with slightly higher prices.

The real treasurese, including the best of the crepe de chine dresses, shawls, blazers, kimonos, even wedding dresse and furs, are in a separate room on the first floor. Classic Clothing includes alterations with the cost of these items.

"Look at this dress for $25," says Jan Hall, holding a draped crepe dress in pink an black. "It's not possible to find this kind of quality and style at almost any price today," says Hall, [WORD ILLEGIBLE] first started wearing old blouses and bed jackets with jeans three years ago and now is "looked" an old jewelry as well as clothes.

"I'd rather spend most of my money on good shoes and bags," say Charlotte Fleming, a teacher. "Few people know that a lot of my clothes are second-hand."

For himself, Streidel often picks up a flannel shirt or sweater from a bin, he says. Leaning over the nearest box, he plucks out a Rogers Peet cut away and laughs."Well, that's not quite my style."

Streidel's been told that some of his clothes were used in the movie "Annie Hall." Classic Clothing has the vests, the pleated pants, the shirts, even the hats to make up the look, but Streidel is skeptical.

"This is much more fun than being on accountant" says Streidel. But what gripes him are the high prices he sees on the old clothes in some stores. "Some are almost as high as new clothing," he says with astonishment. "That takes all the fun away. Old clothes should really be a treasure hunt."