More than 1,500 works of art from the Washington home and office of the late Joseph H. Hirshhorn have been inventoried and moved into storage at the Hirshhorn Museum.

"The museum is acting as caretaker until the art becomes legally ours, and we'll do nothing with it until then," said Hirshhorn director Abram Lerner. "But I can tell you the collection will be enormously enriched by this gift. We're pleased as punch."

Hirshhorn, the uranium mogul and financier who died last August at age 82, left his entire personal art collection--estimated at 5,000 items--"for the exclusive use and benefit" of the museum he founded. The remaining works are stored in three rooms of a New York warehouse, where an inventory is still under way.

The 605 works from Hirshhorn's four-story, 16-room house on Bancroft Place NW and the 939 pieces from his Q Street townhouse/office in Georgetown have been transferred gradually over the past month. "I don't know what to do about all these nails," said Hirshhorn's widow, Olga, who is still living in the house, which is for sale. "Joe hung everything on two nails. There are 120 of them on my bedroom walls," where 60 paintings by American artist Louis Eilshemius hung.

Though no final assessment of the collection can be made until the inventory is complete--and for that reason Lerner declined to release the list-to-date--some of the works in the house were clearly among the most important Hirshhorn owned at the time of his death. They are known to include:

* A major painting by George Bellows titled "Ringside Seats," a prizefight scene due to be shown at the National Gallery of Art next fall.

* Another important Bellows painting titled "Mrs. T in Cream Silk Dress," a portrait which hung over the dining room fireplace.

* "Soft Night," a 1947 painting by Arshile Gorky, purchased by Hirshhorn at a record price of $140,000.

* Two Durer engravings, "Three Peasants in Conversation" and "Peasant and His Wife," which were Hirshhorn's first art purchases, at age 17. He had asked that they be buried with him, but Mrs. Hirshhorn decided against it.

* Dozens--perhaps hundreds--of small-scale sculptures by Degas, Giacometti, Nadelman, David Smith, Moore, Calder, George Rickey and others, which covered mantlepieces and table tops and teetered from various perches throughout the house.

* A powder room full of Picassos.

* Paintings by Georgia O'Keeffe, Raphael Soyer, Richard Lindner, Roy Lichtenstein, John Clem Clark, Richard Anuszkiewicz and four collages by Robert Motherwell.

* A large Henry Moore bronze, titled "Seated Woman," which duplicates a cast already in the Hirshhorn Museum. When asked what the Hirshhorn would do with this and other duplicates, Lerner said, "The board of trustees will have to decide . . . We'll think about these things when the collection is ours." Under the terms of Hirshhorn's original gift to the museum, any works of art can be sold as long as the proceeds are used to acquire other works of modern art.

Asked which of the new acquisitions he considered to be most important, Lerner said he could not judge until he had seen everything. "But in addition to the two major paintings by Bellows, and the Gorky, there are at least four de Kooning sculptures, four Henry Moores, four Nadelmans and bronzes by Maillol and Matisse," said Lerner. "And in the Q Street house, where I had never been, there were lots of surprises, including a big Andy Warhol painting, four Balthus drawings and any number of Picasso prints. We're going to have a great Picasso print collection," he said.

"We decided we could absorb this number of works, but it strains our storage," said Lerner. "What remains in Manhattan will probably have to be stored someplace outside the museum. As to the total number, people are mentioning figures--and all together it may come to 5,000-- but we don't have any real idea."

The museum's gain has been a distinct loss for Bancroft Place, where nothing was left on the walls but bits of masking tape and nails. "This is the first time I've had to live without art for 20 years," said Olga Hirshhorn, whose own substantial art collection is currently on tour. She is also living without the 18th-century American furniture, oriental rugs and art books already sold at auction to comply with the terms of her husband's will. Among them was Hirshhorn's favorite single object, a Simon Willard clock, which was purchased by actor Bill Cosby.

"I didn't have to do everything right away, but I knew it had to go, and it's slow death to delay it," said Hirshhorn's widow. "And as for the art, I wanted them to take it. I felt so vulnerable here. Now I can go away and not worry." She plans a cruise of the Baltic Sea with Coral and Vincent Price this month.

To make the place look slightly more livable, Olga Hirshhorn has hung several photographs of artist-friends here and there on the offending nails. In the dining room, she has covered a folding aluminum table with a lace tablecloth. "The young men from Artransport were worried about me and offered to make a wood frame for my mattress when they took the bed away. That's what I'm sleeping on."

"Now I'll have to do something about all those nails," she said, surveying the vastness. "But if Joe were here," she added, "he'd say that any potential buyer who worried about the nails can't afford the house. And he's probably right."