After thinking about it more: I don't think destroying the old phone (and that's what recycling is) is such a good idea, even if OP's in a country where 3G and 2G are going away. There are still a few possible uses for the phone:
#1: Trade-in value. When buying a new phone, OP might be able to get a discount in return for the old phone.
#2: Even a smartphone with no internet connection, and no ability to make phone calls, still has useful apps such as a calculator. A spare calculator or alarm clock might come in handy.
#3: A decoy. Some folks try to make you give them your cell phone. That's dangerous, because a phone is how you call for help if you're in trouble! If anyone demands that you give up your cell phone (be it a mugger on the street, or a teacher in a classroom), that's a very bad sign. You have to ask yourself just why they don't want you to be able to call for help. It might be good to have a decoy phone, so that you can give that one up and keep your real phone.