Soda cans, orange peels, sandwich wrappers and globs of red-white-and-blue debris littered the Mall to the tune of 45 tons Monday night, a trash haul that was considerably less than in years past thanks to security-savvy revelers who are traveling lighter in anticipation of police checkpoints, officials said.

"We told people: 'Don't pack as though you're going on a 40-day cruise,' " said Bill Line, spokesman for the capital area of the National Park Service. "And people listened. They're getting used to being searched. They're learning to pack like they would at an airport security checkpoint."

Before Sept. 11, 2001, and before alcohol was banned from the Mall, the Park Service worked for days to remove three times this year's amount of trash, and police worked for hours processing scores of arrests they had made.

Revelers used to lug sofas, mattresses, beer bottles, kegs and liquor flasks to the Mall and then leave them behind. In 1996, the year before alcohol was banned, the Park Service hauled away 157 tons of garbage.

"It used to be much, much worse," Line said.

But a loveseat or a keg is difficult to sneak past 20 checkpoints staffed by dozens of police officers hand-searching bags and wielding hand-held magnetometers, a system set up in 2002 in response to the Sept. 11 terrorist attacks, said U.S. Park Police Chief Dwight E. Pettiford.

Weeding out alcohol at checkpoints cuts down on more than the trash haul, said Sgt. Scott Fear, a U.S. Park Police spokesman.

"I've been here for 15 years, and the last three or four years have been completely different," Fear said. "In the past years, we had stabbings, we had numerous fights. It was a whole different atmosphere than what you're seeing now."

Park Police made two arrests Monday, both for narcotics possession, Fear said. At the checkpoints, police seized some alcohol and a few knives, but even the piles of confiscated items are growing smaller every year.

"The public is becoming more and more educated about what to bring, what not to bring and how to deal with a checkpoint," Pettiford said. "The end result is people having a good time, praising the fireworks and feeling safe."

The low arrest rate and garbage tally also do not reflect the size of the crowd Monday night. The Park Service has a policy against making crowd estimates, but Line said the Mall was "pretty densely packed."

"It was a large crowd, even shoulder to shoulder at some points," he said.

Metro reported that 540,875 people rode its trains Monday. With better weather than last year and a ballgame fueling the crowd, the count far surpassed the 363,280 people who rode last year, Metro officials said.

The other good news on the garbage front was delivered Monday night by a shifting wind, which carried most of the debris from the fireworks away from the National World War II Memorial, which was slated to be closed until today for cleanup, Line said.

The debris drifted to the Constitution Gardens area of the Mall, which was closed off while members of the 47-person cleanup crew searched for spent fireworks cartridges or other leftovers.

The World War II Memorial opened yesterday morning, a day early.

The newly opened grounds around the Washington Monument fared well under thousands of feet, Line said. About a dozen arcs of water sprayed over the newly planted sod yesterday to help it recover from its first stampede.

A tarp, being removed by Park Service worker Binh Nguyen, shielded the World War II Memorial from fireworks debris.