With trumpet fanfares from a dozen music students stationed on campus spires, more than 4,000 University of Massachusetts students and other volunteers launched a four-day clean-up Thursday of the university's troubled 28-story library.

University officials estimate the volunteer project will save it about $500,000 and drum up some pride in the library, which has led to more jokes, legislative inquiries and engineering reports than term papers over the past decade.

The undefeated football team, ranked 12th in the nation among I-AA schools, has even vowed to ferry 18,000 lightbulbs from the basement to the top floors in a stairway scramble that university publicists have dubbed the "Charge of the Light Brigade."

The 13-year-old library has been the butt of jokes since chips and chunks began falling from its massive brick facade shortly after it opened in Amherst. The fallout got so bad that it was ordered closed for a semester in 1979 and has seen limited use since.

For years, hay bales surrounded the building to cushion the plummeting facade and frustrated scholars, who did manage to get at its 2 million books, decorated the library's walls with terse commentary on the elevators that didn't work, the roof that leaked, and the books that were lost in the shuffling back and forth between libraries when the tower was closed.

When a suggestion was floated to name the building, which houses the papers of W.E.B. Dubois, after the black separatist born in Great Barrington, the Black Student Union rose up in protest. To this day the library lacks a name.

Even its billing in the Guiness Book of World Records as the world's tallest library was disputed by the University of Texas, which claimed that its 307-foot high tower, which houses administrative offices as well as books, is 11 feet taller.

Duffey ordered the hay bales removed two years ago, but no solution has been found for the building's nasty habit of shedding bricks.

After engineers threw up their hands, the chancellor directed the $2.5 million the legislature appropriated to fix the bricks in 1980 used to complete two unfinished floors, repair the elevators, put a roof over the entrance to protect scholars heads and replace the chainlink fence and saw-horses, aimed at keeping students at a safe distance from the building, with shrubbery.

After the student clean-up, the library is scheduled to be open for full use for the first time since it was built.