At least three companies have targeted a tiny Brooklyn neighborhood with their gaudy clothing-collection bins — rankling locals who are wondering who’s profiting from the clothes off their backs.

The nonprofits Planet Aid and Helping Hands of PA, along with for-profit USAgain, have set up the metal contraptions along Smith Street and elsewhere in Carroll Gardens, soliciting donations that the groups claim help the less fortunate or the environment.

Chicago-based CharityWatch told The Post it is giving Planet Aid an “F” for fiscal year 2011, for spending only 29 percent of its budget on programs.

“If you really want your clothing to do something charitable, sell them yourself or donate them to a highly efficient charity whose values are in line with your own,” said CharityWatch analyst Laurie Styron.

Planet Aid and Poconos-based Helping Hands of PA — which listed no income on its 2011 tax return — did not respond to calls.

Chicago-based USAgain said it bundles the clothes and sells them to wholesalers.

“Instead of throwing away unwanted clothes, consumers can drop them off in USAgain’s bins, knowing they will be diverted from landfills to be reused or recycled,” said a spokeswoman.

After a Post inquiry, the city says it will be inspecting all bin locations.