Flip-flops are a staple of casual summer fashion, and at prices as low as $2 per pair, they're hard to resist. But when it comes time to stock up on new pairs, what do you do with last year's worn out ones? Take them to the store with you. Old Navy stores nationwide, including locations in Wilkes-Barre and Scranton, are collecting used flip-flops through May 21. The shoes will be recycled into playground equipment by TerraCycle, an international company that recycles products that are typically thrown away. The flip-flops will be shredded, melted down and made into small plastic pellets, said Megan Yarnall of TerraCycle. The pellets make plastic boards used as structural pieces for playgrounds. Consumers can deposit flip-flops in cardboard collection boxes located inside the store, said Jeni Alexander, Old Navy district manager.