Recycling in New York City didn't entirely go away in the last two years. But it got as confusing as a game of Twister. First, in the summer of 2002, the programs for glass and plastic were suspended. Metal and paper recycling continued. Then plastic came back last summer, but not glass, which still had to be tossed in with regular trash. A further complication was a switch in recycling collections to every other week, instead of weekly. It all left city residents puzzling over their garbage, Hamlet-style: to recycle or not to recycle, that is the question.

While the city may have had the best of intentions in suspending parts of the recycling program, the experiment did not produce the savings predicted. All those items that could have been recycled were trucked to increasingly expensive landfills, part of the city's 12,000 tons of daily residential and institutional trash. And what wasn't factored into the cost-benefit analysis was the psychological effect on New Yorkers, who had just started internalizing the recycling routine. In 1989, fewer than 1 percent of city residents sorted their newspapers, cans and cartons. By 2002, about 20 percent had the habit. Recycling takes effort, but residents were coming around to seeing it like daily exercise: not always enjoyable, but good for them.

For confirmed recyclers, tossing bottles in the trash again brought a certain trauma, or a thrill of rule-flouting. Then some got used to promiscuous trash-tossing, and their garbage bags took on the look of a slacker, with unsightly bulges. Reasserting rubbish discipline may not be easy. The Natural Resources Defense Council, an environmental nonprofit group, has helped by paying for subway ads promoting recycling. The city's own re-education campaign includes instructive fliers in newspapers, but cries out for more fanfare. It's up to the city — and Mayor Michael Bloomberg in particular — to send strong signals that recycling is back for good and that the city takes it very seriously.

When the mayor cut back, he promised to study the recycling issue, so he deserves credit for following through and reinstating the entire program. Now it's time for Mr. Bloomberg to use his considerable sales skills to persuade New Yorkers to get back on the wagon.