About 600 million obsolete cellphones are languishing in U.S. homes and offices. If you have one, you can recycle it—and do a good deed.

Log on to www.gooddeedfoundation.org/aarp and follow the easy prompts. You’ll receive a postage- paid envelope or a collection box for community phone recycling efforts. Some phones will be sold, with the proceeds going to programs that help women and children escape poverty or to support climate-change initiatives. And some will go to older adults so they can make 911 calls.

“People can make a huge difference through this program just by giving away something they’re no longer using,” says Calandra Cruickshank, executive vice president of the Good Deed Foundation in Phoenicia, N.Y., which is cosponsoring the effort with the Environmental Media Association.