You still have two more days to get rid of old keys while saving the planet and helping the homeless at the same time.

The Harvard Office of Sustainability, in conjunction with the Whole Foods in Medford, is collecting old keys to donate to Key For Hope, a Massachusetts charity. The profits from recycling the keys donated to the Medford store will then be used to purchase food for the homeless at cost, according to Jennifer Kump, the store’s marketing team leader.

This is an easy charity project for people to participate in, Kump said. “[Keys are] something I know we all have at home.”

To participate, send your keys by University mail to 46 Blackstone St.