I admit that my running shoes are past their prime. The rubber sole under my heel is beginning to look a little crushed, and my knees are more sore than usual after my latest long run.

As a runner, I know I should replace my shoes every 300-500 miles. For me, that adds up to at least two pairs of shoes per year. I don’t have the room in my closet to keep my old Saucony Rides (even if they do hold a special place in my heart for helping me cross my first finish line), but I don’t want to just throw them away and add more waste to our landfills.

So what’s an eco-conscious runner to do? If you’re in the Chicago area for the Chicago Marathon this weekend, you can drop off old running shoes until Oct. 16 at 33 Bank of America locations for Nike’s Reuse-A-Shoe program. This program is available year-round at Nike retail stores (find the one nearest to you), but it’s super convenient for those racing this weekend. (They can donate their shoes immediately after the race at the post-race party.)The Reuse-A-Shoe program turns all parts of your shoe into something useful. The fabric, foam and rubber get new life as basketball courts, tennis courts and tracks, respectively. Talk about a great way to reuse a shoe. Check with your local running store as they may collect shoes for recycling as well.If you want to be greener from the get-go with your running shoe purchase, Brooks has come out with a biodegradable midsole. According to their site, traditional midsoles can last up to 1,000 years in a landfill. The Brooks midsole, however, will break down in 20 years, saving 29.9 million pounds of waste.Of course, if your athletic shoes still have some life in them, you can donate them to a local charity.As for me, I’ll be sure to drop-off my old shoes for recycling when I buy those new ones.Are you trying to run but can’t find the time? Or perhaps you’re looking for a way to spice up your commute? Check out what actor Joseph Fiennes suggests.