At the all-day event, in its fourth year, more than 50 graffiti writers painted over the exterior of the TerraCycle factory and garage on New York Avenue.

Their bright, colorful work made the compound look more exciting, said Tom Skazy, TerraCycle's founder and chief executive officer.

"We get a much higher-energy building," said Skazy, 26. "People really like that."

The graffiti writers, from New Jersey, New York and Pennsylvania, worked around heaping piles of worm waste, the primary ingredient in the eco-friendly company's 11 varieties of lawn and garden fertilizer.

The excrement didn't seem to bother the writers, many of whom said they were pleased to be able to collaborate with fellow artists.

Rolo Vasquez, 25, who spray-painted several large faces on one factory wall, said he was at the jam to "share with other writers."

Vasquez, a native of Santiago de Cali, Colombia, called graffiti more expressive than other visual arts.

"You can have more fun," he said.

Leon Rainbow, a local writer who helped organize the Graffiti Jam, painted his nickname, "Rain," with each letter in a distinct style and color.

"I wanted to showcase different styles in the same piece," said Rainbow, 32, who has been painting graffiti for 10 years.

Skazy, who founded TerraCycle in 2001, said the event had gotten started when he heard from local police that many graffiti writers were being arrested.

He told the officers: "Well, we have this building that's pretty ugly. Why don't we just have them paint the building?"

Skazy said one of the goals for the event was to erase the stigma surrounding graffiti.

"What we don't want to do is make graffiti seem like it's just really thuggish," he said. Here, the writers "get to really express exactly what they want to do."

Before the jam, the company paints over the previous year's designs in black, giving the writers a fresh canvas.

Several people who showed up to watch the writers said they were impressed.

Van Williams, 64, who stopped with his wife, Myra, 67, on their way to a farmers market, said the event allowed the writers to demonstrate their skills without breaking the law.

"It gives them a chance to show their talents," he said. "It isn't doing anybody any harm. It's actually probably making the place look a little better."

Steve Nicholson, 47, who is TerraCycle's warehouse distribution manager, brought his wife and three children to the event.

Nicholson's 8-year-old son, Matt, was quite taken with what he saw.

"I want this painted in my room," he said excitedly.