"It was Saturday, I was working review," says Bryan VanSweringen, sounding like Jack Webb kicking off a recycled "Dragnet." "So I started flipping through this letter. I thought, 'This has a good chance to be real.'"

It was VanSweringen had dug up a letter written by Fidel Castro as a boy of 12 or 13 to Franklin D. Roosevelt in November, 1940, asking for a $10 bill and saying that he knew of rich iron deposits just uncovered in Cuba. Like an 1849 gold prospector suddenly onto something, vanSweringen had stumbled across the kind of nugget that encourages him to keep digging.

He can use encouragement. An aspiring archivist, vanSweringen, 24, works at the Washington National Records Center in Suitland, declassifying documents. The building is the size of three airplane hangars and contains enough paper to keep him and his colleagues reading until they're 65, or more. In his division, the overflow of permanent materials from the National Archives, there are about 400,000 boxes of records. And that doesn't include an even bigger paper mountain, 2.6 million boxes of federal agency records, most of which eventually will be destroyed. In all, the place contains at least 7 1/2 billion pieces of paper.

Anything can be found, from Army Vietnam records (20,000 boxes) to reports on the numbers of coos made by mourning doves. There are 43,000 boxes of passport applications, Coast Guard ship logs dating from the 1950s, hundreds of thousands of pension claims; in the Archives division, there are records of labor strikes from 1913 to the 1950s, U.S. District Court records from 1801 to 1926, 8,500 boxes of State Department foreign service files, more than 1 million land records, 35,000 boxes on World War II military units, Navy muster roles from 1868 to 1956. Also: one volume of "Aunt Sammy's Radio Recipes," Depression-era radio spots on how to prepare meals cheaply.

There are even filing cabinets full of the paperwork (Standard Form 135) needed to shuffle the paperwork into the building from the agencies.If the Smithsonian Institution is the nation's attic, the records center has become the government's garage, its motley contents inexorably rising to the rafters.

Still, picking through the dusty mounds has its moments of discovery.

"We find lots of fun things," says Brenda Reger, head of of an Archives group that is declassifying papers as old as 1890, though most of it was World War II records "One time a fellow found a practice hand grenade among some ordnance records, although we didn't know it was practice until he dropped it. He held it up and said, 'Look what I found,' and then he accidentally dropped it. Everybody in the room went under the table."

Reger had on her desk a black, three-ring loose leaf book filled with page after page of descriptions of obscure World War II committees - "a whole book of Roosevelt concoctions." Smiling, she turned the pages. "Here's the 'Advisory Committee for Developing a Simplified List of Sizes for Pallets and Skids.' Here's the 'Advisory Committee on Tires and Tubes.'"

Her office, though large, is like a cell in a space colony, the place is so immense.

Carlton L. Brown, the center's director, leads a visitor into the bowels: past a door with a sign that says, "restrict area, badge or escort required;" up a wide ramp that resembles the cargo entrance to the Astrodome; down a long hall to a gigantic, sliding door. He pushes a button and a door opens, revealing an even longer concrete hallway - maybe 200 feet - and seemingly endless rows of shelves filled with tan cardboard boxes."This is a storage module," says Brown. "There are 200 storage modules." ("If you've seen one stack, you have certainly seen them all," another official said).

Each module has 14 levels of shelves up to the ceiling. "The bottom seven shelves are used for active records," says Brown, "the top seven shelves are used for less active records. This cuts down climbing the ladder." One of these brobdingnagian creations was parked nearby. It was labeled "No. 9," with the notation, "Move this ladder only in rows 85 through 89."

Brown pointed down the aisle to what at first seemed a speck on the horizon, but turned out to be a woman pushing a cart of boxes, refiling. At that moment, she was finding the proper niche for a patent application on an invention called "remotely connecting flowlines" - "something to do with oil drilling," one man speculated. Brown says that in the last fiscal year the center answered 679,424 requests for materials from government agencies or individuals, taking down the stuff, then putting it back.

In Room 143, a concrete block enclave, is hung a large picture of an old Washington Senator's team (an appropriate archivist's decoration), a baggy-pants group jauntily running onto a field, apparently for the start of spring training. In another large module, James Miller, wearing the archivist's traditional dust jacket, is busy at his desk between shelves 42 and 43 organizing the files of Joseph Ames, a former president of Johns Hopkins University and chairman in the 1920s and '30s of the National Advisory Committee for Aeronautics.

Miller's workspace is being converted into a huge vault, the door of the place resembling a gigantic safe door with a combination lock. "Within the last six months," he said, "two government officials got locked in Vault 3. It was really their own fault, they entered at 4:25. I said to the guy who closed up, 'Did you see those two guys?' He said, 'What two guys?'"

Trying to explain the meaning of it all, Miller's boss, the head of the Archives division, Daniel T. Goggin, wearing a three-piece gray suit, said, "We're referred to in-house as a cutodial unit. We're custodians, not moppers of floors."

Goggin pulled from his office shelves several thick books, guides and inventories that his department complies and updates; such as the 884-page Guide to the National Archives of the United States and the Guide to the Archives of the Government of the Confederate States of America. He said that a guide to American women's role in history, already an eight-year project, is nearing completion. He displayed 'Preliminary Invetories, Number 157," dated 1963, one he had done himself. "This one took six years," he said, smiling, and patting the book.

Two other major projects are OMGUS and SCAP. OMGUS, the Office of Military Government for Germany (United States), involves the records of the U.S. occupation of Germany after World War II which are being microfilmed by a team of Germans for the West German archives, the Bundesarchiv, in Koblenz, and five German state archives; SCAP means Supreme Commander Allied Powers and involves the records of the U.S. occupation of Japan, an upcoming project.

Goggin introduced three German team members, who said that 14 months of the five-to-seven year work has been accomplished. They are microfilming 9 million frames, which, one said, "is only one-third of the OMGUS records." The importance, they explained, is that the West German history of the late 1940s, "down to the village level," is here, not in Germany.

"It is a revolution," said Klaus Oldenhage, a Bundesarchiv official; describing the microfilming procedure.

"That's going too far." suggested Brewster Chamberlin, an American and former University of Maryland teacher, abroad now with the Institute for Contemporary History in Munrich. "But nothing like this has ever been undertaken before."

"I have never dared to calculate," said Wolf Buchmann, also with the Bundesarchiv. He says that the Germans are paying the National Archives $380,000 for the microfilming but as for one minute." The three converse in German and some figures are written down.

"One million dollars," concludes Brewster.

"More," says Buchmann.

"More," adds Oldenhage.

The biggest chunk of ht e paperwork, though, is of too little use to keep forever. "We bring it in and we throw it out," says Jack Bumgarner, a 32-year veteran in records. He has three 7 1/2 ton tucks which make regular pickups at government agencies. But he adds that when the loads get too large, agencies haul them themselves; HUD recently dropped something like a ton of paper on him and even more - Library of Congress material - is soon to hit.

Bumgarner does not discoverage easily. "In years gone by," he says, agencies. But, I believe it was '73, they had to come up with a schedule providing a certain date when the material could be disposed of. This helps us move it out."

Most of the stuff is hauled by a private company and ends up re-cycled in a paper mill. Bumgarner says this is a much more sensible means of disposal than a giant macerater, sort of the piece de resistance of shredders, that was built into the building and used until three years ago.

"That was a big headache," says Bumgarner. It took a man to operate it every day, it was noisy, and, says Bumgarner, "we had to pay somebody to haul away the by-product." And that is how the records center came to make its biggest disposal of all, its own shredder. It was too big for any buyer, and so went for scrap.