Garbage in the subway system – which totaled 30 million pounds last year – can seem to take on a life all its own. Take, for example, the Atlantic puffin that sat quietly next to Kate Levedeva aboard an uptown 5 train yesterday.

The puffin, of course, usually lives off the coast of Maine, except when its likeness appears on the cover of the April edition of Yankee magazine, which its last owner ripped asunder, and then abandoned, on the subway seat.

By the time the train got to Union Square, all the seats were taken, including the one occupied by the disheveled magazine. Luckily for Ms. Levedeva, she got on at an earlier stop, sparing her from the dilemma that even the least hygienically inclined subway rider faces from time to time: whether to touch the mysterious scraps – napkins, newspapers, crumpled bags – in order to claim the subway seat the detritus is occupying.

“If I don’t have to, why touch it?” Ms. Levedeva, 30, asked. “There was a seat next to it, so I just took it.”

Fortunately for the transit workers whose job it is to pick up the 15,000 tons of trash left behind by the 1.4 billion riders last year, another straphanger eager to sit removed and pocketed the magazine.

Not all garbage, however, leads a harmless life. On Tuesday, debris on the tracks and a spark from the third rail started a fire near the Atlantic Avenue station that halted the morning commute for thousands of riders and sent five people to the hospital.

Until a fire on January 23 shut down the A and C lines for nearly two weeks, major fires were infrequent. Small ones, on the other hand, were sparked about four times a day, according to New York City Transit records.

Many blazes originate from the smallest form of subway garbage: steel dust, the highly combustible shavings from the subway’s rails. The subway’s answer to this hazard since 1998 has been the yellow industrial-strength train that crawls through stations at two miles an hour, affectionately and descriptively known as the Vak Train.

There are two Vak Trains in the subway system. Last year, they sucked up 1.4 million pounds of garbage on the tracks.

For the remaining 28.6 million pounds of garbage, there are the roughly 200 transit workers who must contend with the insensitivities of riders like Roy Jonson.

Standing on the platform of the 2/3 train at Times Square yesterday, Mr. Jonson, who is a construction worker, unpeeled a Band-Aid and threw its wrappings onto the track. He defended his actions with a peculiar brand of logic.

“It stinks down there,” Mr. Jonson, 46, said. “That’s why we have to throw garbage: So they get the message they have to clean it.”

When told that transit workers indeed clean the subway, Mr. Jonson quickly parsed those words.

“They don’t clean,” he said. “They attempt to clean.” Then he came up with a novel idea: scented deodorizers throughout the subway because, as Mr. Jonson said, “good smells soothe the mind. You smell something bad, it makes you mad all day,” he said.

Fortunately for transit workers, for every Roy Jonson there is at least one Paul McClure. Sitting down on the no. 2 train yesterday afternoon, Mr. McClure promptly snatched up a copy of a catalog from the Design Center, a Home Depot company, long forgotten by its original owner. Mr. McClure is an artist who might find something of inspiration in the catalogue.

“I find things all the time” both on and off the subway, he said. His leather gloves for example, or the odd newspaper.

“I know it’s only a saving of 25 cents, but I very rarely read the news,” Mr. McClure, 56, said. “If I find something I’m interested in, I’ll take it; if I don’t, I’ll just put it back.”

The catalog he tucked inside a canvas bag, right next to the newspaper he found in another garbage can.

Of course, there is a line to be drawn, where refuse is no longer in the eye of the beholder, where some items are clearly meant for one place only: the garbage can.

“Garbage,” Mr. McClure said, speaking of it in its most unmistakable form, “I find it disgusting. I love it when I find a clean subway. I just can’t imagine people throwing away something on the tracks, period, whether its going to start a fire or not, you know?”