Recycling is a big part of making the earth a greener and healthier place for everyone, and every little bit helps. This week is Earth Week, and if anyone is unsure of how to celebrate the holiday, Old Navy has a suggestion - look through the closet and try to find old pairs of flip flops.

From April 22 to May 21, Old Navy stores across the country will be taking in worn-out sandals through an initiative called Flip Flop Replay, which the company is launching with the help of trash-to-treasure company TerraCycle.

This initiative is especially important, because flip-flops are often made from toxic materials such as PVC and polyurethane, according to The Huffington Post.

The benefits will reach beyond recycling, too - the materials from the old flip-flops will be donated to four different playgrounds to create safe, rubber flooring underneath all of the equipment.

"They're almost considered a disposable item," Greg Roth, the Northern California district manager of Old Navy, explained to The Record Searchlight. "The basis of this program was: How could we sell product and look at it from an environmental standpoint?"

Office Depot has also paired with TerraCycle to start another program that helps people recycle their office supplies. The stores will be accepting mechanical pencils, pens, dry erase markers and highlighters. In return, shoppers will be given gift certificates.

"Pens can be made into new, useful products," Ellen Bishop, a merchant who deals in writing instruments, told the news source. "There's no need to fill your landfill with pens that don't work anymore."

TerraCycle has previously been involved in recycling programs with other companies. Stoneyfield Yogurt teamed up with the organization to turn old yogurt containers into toiletry items such as razors and toothbrushes, according to ChildMode.com.