It could be your grandmother's parlor, this room with the heavy gleam-polished furniture upholstered in ornate brocade. Or the living room of the elderly neighbor lady whose myriad porcelain figurines, fine teacups and heavy silver were displayed behind glass. Stiff portraits of distinguished family members stare soberly from above the mantle. Only the resonant ticking from the tall case clock breaks the silence.

This is one of the period rooms at the headquarters of the Daughters of the American Revolution, whose museum devoted to American decorative arts dating from before the Industrial Revolution is probably one of the city's best-kept secrets. This is a place to wander unhurried through dozens of rooms full fo bric-a-brac, old clothing and memorabilia from prominent and ordinary citizens.

The building itself is elaborate: a Beaux Arts structure built at the turn of the century with ornate molding, hanging chandeliers, dramatic skylights and dated formality. Temporary exhibits from the museum's permanent collection of textiles, glass and furniture are showcased in the upper tier of the DAR library, which served as the auditorium until the current one was built.

It's a pity the museum is low on funds and understaffed, because the curator is hardpressed to find the time to develop well-thought-out exhibits, let alone to catalogue nearly half of the 35,000-piece inventory.

Because the museum relies heavily on donations from members, verification is essential - one well-intended member contributed a pair of white satinshoes, saying they'd been worn by Benedict Arnold's bribe at her wedding. Until their authenticity can be validated, the slippers, like a number of other "unknowns" are relegated to the "junk room," a small chamber off the permanent exhibit hall. Historically uncertain these items may be, but this room is as fun to go through as anyboby's attic: elaborate compasses doubling as sun dials in hand-tooled leather cases, grease lamps of forged iron, a milk skimmer, candlemold, 19th-century curling iron, primitive handcuffs, boot hooks and shot bag.

Another case holds First Lady mementos: a lace handkerchief and stationery belonging to Bess Truman, an old DAR pin, Mrs. Warren G. Harding's French leather gloves, a cake box from the wedding of Frances Folsom and Grover Cleveland, a setting of particularly gaudy-gold-leaf crystal and dinner ware belonging to the Hardings.

But this is only one part of the museum. Nestled in nooks and crannies on all floors are 29 state rooms, which attempt to recreate the flavor of the period when the state came into the Union. Among the most successful is the California adobe parlor circa 1850, recreated from letters and records with a rustic flavor.

There is also an exhibit on George Washington memorabilia, proof of that tourist knick-knacks are not a recent development. George's face and name appeared on virtually everything from a Masonic Temple apron to bedsheets and handkerchiefs. But none seems to top the tumblers sold after his death, with the first president's somber face staring at the drinker from the bottom of the glass. CAPTION: Picture, A BOWL OF SOFT PORCELAIN, MADE IN WORCESTER IN 1770-1775, FROM THE DAR MUSEUM.