Bye-bye, BORF.

The yellow sidewalk painting signed by the omnipresent graffiti "artist'' disappears into a colorful puddle after Bernard Green blasts it with a water jet pressurized to 3,500 pounds per square inch.

Green and his co-workers from the District Department of Public Works are soldiers in a long-running war against graffiti in the city. The players, the locations, the styles may have changed over the years, but the theory remains the same.

"You put it up, we're going to take it down," said Michelle Rucker, who supervises the three DPW graffiti removal teams that responded to 1,121 complaints in 2004, up from 600 the year before. The city also pays a private contractor to clean graffiti high above street level.

The crews tackle the complaints as they come in, although gang graffiti and vulgarities jump to the top of the list, said Dennis Butler, DPW's program coordinator. The service is available free by calling the Mayor's Citywide Call Center at 202-727-1000.

The city will automatically remove graffiti from vacant structures and requests permission to do so from the owners of occupied ones. Sometimes gaining permission is surprisingly difficult. In one case, an owner refused to allow the crews to remove graffiti on her home because she feared that the power-washer would damage the building. She was finally persuaded otherwise. Afterward, she was so happy with the work that she exuberantly thanked the crews and took photos of their handiwork.

"I think it's great," said Guang Li, the owner of a building on Ninth Street NW. One day last week he saw the crews working down the street and asked if they could blast some graffiti off the side of his building. The only persuading Li needed was that it was free.

Butler and Rucker said gang-related graffiti has exploded in recent years, and DPW crews sometimes are accompanied by police when they remove the "tags," or letters and symbols that represent a gang.

At Harriet Tubman Elementary School at 13th and Irving streets NW, the graffiti removal crews will soon come back for a fourth time to paint over the spray-painted "STC,'' the initials of a Latino gang also known as Street Thug Criminals, and "LV,'' which stands for Vatos Locos, a rival gang.

"We do all we can do," Butler said. "We fall behind, get ahead, fall behind, get ahead."

Gang members use graffiti to mark their territories, and the prevalence of their tags is a good indicator of gang activity. The greatest numbers of graffiti sites are in Adams Morgan, Columbia Heights, Mount Pleasant and Shaw, all fast-gentrifying areas where rowhouses now fetch upwards of $700,000, Butler said. Metropolitan Police Chief Charles H. Ramsey declared a crime emergency to deal with gang-related violence in Columbia Heights and Mount Pleasant two years ago.

The crews get rid of graffiti in one of three ways: scraping, painting or blasting.

In addition to wall writings, the DPW crews also attack what they call poster graffiti: political and entertainment ads. Some posters are softened and then scraped off. The crews enforce the city limit on three political signs per block and a ban on entertainment posters. That's why one of their trucks was filled with ripped-down posters advertising new albums by Boyz N Da Hood and Jermain Dupri.

Other posters and graffiti are simply painted over, which was the fate of posters advertising the movie "Harold & Kumar Go to White Castle" and an old Bush/Cheney sign.

Then there is blasting graffiti away. First, crews spray on a chemical cocktail called Taginator, which Butler says breaks down the paint pigment. They let it work for a few minutes and then blast it off with pressurized water.

Sometimes these city workers must ponder something slightly deeper than whether to blast or scrape, such as, what exactly constitutes art? In the 1500 block of Ninth Street NW, portraits of Harriet Tubman and Langston Hughes, painted on a boarded-up window, counted as art. BORF's yellow blobs on the sidewalk -- signed "BORF '04" -- didn't.

Merrit Drucker, the District's Clean City coordinator, said it is difficult to say whether the city is winning the war on graffiti.

"My sense is that we're making progress," he said. "It seems to come in waves. As vacant buildings are occupied, people move into the city and the commercial corridors get filled, it will decrease."

Drucker said the program is also looking into strategies that are more high-tech than water and paint, such as new graffiti-repellent coatings that could be applied to streetlight bases and traffic signal boxes, two strong magnets for posters and scribbles.

Drucker is also working with the Washington Metropolitan Area Transportation Authority and CSX Inc. to help clean up railroad corridors across the city.

Drucker commutes to work on the Red Line from Takoma Park every day and said he takes personally all of the graffiti he sees on railroad bridges and other bridges and overpasses.

"It's frustrating," he said.

Besides the public works crews, the city's parks department and the Downtown D.C. Business Improvement District have their own graffiti removal efforts.

Frank Russo, the deputy executive director of the Downtown BID, said his 45-person cleaning crew has orders to remove graffiti within 24 hours.

"Experience has shown that the quicker you get it off, the less it will occur," he said. "I guess there's no value in risking getting arrested for graffiti if your artwork will only last for a short period of time."

He said the BID tracks graffiti by location, and 110 areas were hit last year within the BID's boundaries of the U.S. Capitol, Constitution Avenue, 16th Street NW and Massachusetts Avenue NW.

Private businesses and homeowners also wage war on taggers and painters.

At Jarboe Printing Co., on Oglethorpe Street NW, workers are nearly obsessive about keeping their property shipshape.

"It's philosophical," said Jarboe Vice President Ted Eby, who had walked around the property earlier that day to see if anything was amiss. "We have an owner who is 87 years old, and that's the way he likes his ship."

Eby said the company has put up fences and barbed wire to deter graffiti artists, but a couple of times a year the vandals prevail.

"I don't know how they get over the fences, but they do. Maybe they build a trench,'' Eby said.

The Jarboe building may appeal to graffiti painters because it is visible from the nearby Metro tracks.

But that visibility also helps the company. Eby said he sometimes gets calls from customers on the Metro who know the company would want to know immediately if graffiti is on their property.

Eby said some of the graffiti artists are talented, but there is no excuse for doing it on private property.

"They should use their talent,'' Eby said. "But in some other way.''

Linda Bethea, an employee of the city's Department of Public Works, paints over graffiti around Ninth and Q streets in Northwest.Department of Public Works program coordinator Dennis Butler, above, says gang graffiti and profanity jump to the top of his removal list. At right, Linda Bethea, left, and Mary Gary mask graffiti with brick-colored paint.Graffiti that was sprayed with solvent starts to drip before being blasted away with a pressure washer.Below, a paint-dissolving solvent begins to work on some graffiti along 9th and Q streets in Northwest, making it easier for Bernard Green of the Department of Public Works, left, to blast it away with a pressure washer. DPW's three graffiti removal teams sometimes have to paint over graffiti or scrape it off. Graffiti that was first sprayed with a solvent is blasted away with a pressure washer by the Department of Public Works.