Kyiesha Kelly was up late washing dishes one night in December when she heard the rumble of a truck outside. Peering out the kitchen window in her apartment, she spotted several men dragging a huge used-clothing collection bin from a truck across the street to the sidewalk in front of the community garden that she helps run in Bedford-Stuyvesant, Brooklyn.

“We’re responsible for that sidewalk and we have to keep it clean,” said Ms. Kelly, who ran outside to confront the men. “I told them they had to move it, we didn’t ask for it. But they just started to act like they didn’t understand what I was saying.”

She dashed upstairs for her camera. When she returned, though, the truck was gone. The bin, from Narciso Recycling Company, remained, a high-minded motto stenciled on the side: “Through Your Donations We Provide Money to Charities & Give Employees Occupation.”

Not exactly.

A growing number of companies — many of them based in New Jersey — are illegally placing used-clothing bins throughout New York City, blocking sidewalks and serving as magnets for litter and graffiti. The receptacles typically have signs that indicate donated goods will go to the poor or, in some cases, to legitimate charities. But, city officials said, the needy do not benefit from much of what is collected. Instead, the clothing is often sold in thrift stores or in bulk overseas, with the proceeds going to for-profit entities that can be impossible to trace, or even to contact.