Althea Yelverton cleans to live. Five nights a week, inside a nearly deserted office building, Yelverton has swept dirty halls and neatened silent rooms. She has wiped toilets and dusted desks. Only shadows watched. "Chump change," she grumbled, "making nothin' but chump change."

The work is tiring, Yelverton said, and it pays just $4.75 an hour. "A lot of times it's hard to get by," she said. "But I can't afford to quit. It's not a real spectacular life."

Complaints by Yelverton and hundreds of other janitors at downtown office buildings in the District have led to a new labor union drive to seek higher pay and better benefits for cleaning workers. Last month, the Service Employees International Union set up a new unit, Local 525, with "Justice for Janitors" as its slogan.

The local, which has called for a $1.75-an-hour wage raise, a nearly 37 percent increase, says it represents 1,300 of the 6,500 janitors employed at commercial office buildings in downtown Washington. The local does not represent janitors employed by federal agencies or suburban firms.

"We're tired of having no benefits and making what we make," said Yelverton, 26, who holds a daytime job as a cafeteria employe. "The union can help us get some respect and more money."

Two days after being photographed for The Washington Post inside the Southwest Washington office building where she worked, Yelverton said she was fired from her janitorial job by her employer, United States Service Industries, a firm that provides cleaning service for office buildings. Union officials confirmed Yelverton's account.

Richard Gallaher, vice president for operations of the company, said her dismissal was "indirectly related" to the Post photo. In the past six weeks, Gallaher said, Yelverton had twice been reprimanded for misconduct. She was fired Thursday after a dispute with her supervisor stemming from the photo incident, he said. Yelverton later disputed Gallaher's statements.

In its organizing drive, Local 525 has cited seven key demands, including a $6.50-an-hour wage, improvements in sick leave and health insurance, more paid holidays and vacations and fairer treatment on the job.

Union officials contend that low wages often leave janitors trapped in poverty, lead to sloppy work and cause high turnover -- a problem that the union says frequently increases the work for those who remain on the job.

"These people want to be able to do a decent job," said Jay Hessey, director of the local's Justice for Janitors committee. "They're not just the stereotypical shiftless person. For many, this is the only job they can find."

Union surveys in the District have shown that about half of all building cleaners depend solely on their janitorial pay and have no other job, Hessey said.

Managers of cleaning service companies and office buildings dispute the union's claims. They contend that most janitors work mainly to supplement wages from other jobs. In addition, they argue, full-time janitors get higher pay and more extensive benefits than part-time cleaning workers.

"No, you could not support your family on what these janitors make, but these jobs are not designed that way," said Donald Slatton, executive vice president of the Apartment and Office Building Association of Metropolitan Washington.

Almost all building cleaners work part time, Slatton said, and often for only a few months at a time -- to make extra money for Christmas shopping, for example. "It's a very transient type of work."

"A very high percentage of this work force uses these jobs as a supplement to their regular income," said Richard Thompson, president of General Maintenance Service Co., among the largest building-cleaning contractors in the Washington area.

Officials also pointed to Maryland and Virginia, where minimum pay for janitors is $3.35 an hour, the federal minimum wage. According to District officials, many janitors in suburban areas earn about $4 an hour, slightly more than the federal minimum but less than the D.C. pay level.

In the District, janitors employed by private companies are required to be paid at least $4.75 an hour, up from $3.70 in 1986. The D.C. Wage-Hour Board, which sets minimum pay rates for employes in the city, voted last year to raise the minimum wage for "light cleaning" workers, a category that includes office building janitors, to the current level.

Richard Seideman, the board's executive secretary, said the minimum wage was increased to bring the level closer to what is considered an adequate income for a single person living alone in the District -- currently estimated at $13,564 a year, or $6.52 an hour.

Many D.C. janitors viewed the pay raise as inadequate. "Those people squeeze eight hours out of you in four hours, and then give you no job security, no good money," said Willie May Kepney, 52, who works in a cafeteria from 6 a.m. to 2 p.m. weekdays, then cleans a Pennsylvania Avenue office building for five hours each weeknight, beginning at 5:30 p.m. "And my poor little feet are sore. They don't hardly care about us at all."

The union began its organizing campaign last summer, with petitions, sidewalk protests and advertisements on buses and radio stations.

Local union leaders, citing recent studies, have argued that the District's minimum wage for janitors remains lower than the national average, estimated at $6.47 an hour. Janitors in Washington earn less than those in other major cities, they say.

Washington janitors' hourly wages rank slightly below the national average, according to a 1986 survey of 26 cities by the federal Bureau of Labor Statistics.

Under the "light cleaning" category, New York and San Francisco janitors were paid nearly twice as much as Washington janitors. Janitors in Boston and Philadelphia were paid at least $1 more an hour than those in Washington, according to the report.

But in Denver and Pittsburgh, janitors get about the same hourly wage as that set in D.C. Janitors in Atlanta, Baltimore and Dallas had lower pay, generally less than $4 an hour, the report said.

Hessey said that Local 525 hopes to negotiate with local office building owners, who hire cleaning contractors. "This is one of the hottest business climates in the country," he said. "Building owners can afford to pay decent money."

Under federal labor law, the union can gain the right to negotiate on behalf of the janitors either by winning an election among a company's employes or by persuading a company to recognize and bargain voluntarily with the union.

Yelverton has become a union activist, urging other janitors to join up. "Now, when I go down those halls at night," she said, "I stop in the rooms and tell them, 'Y'all better speak up, you hear me, because all you're getting is your chump change.' "