Guitar strings are typically made out of steel or other metal, and occasionally out of nylon. They always have small metal parts and usually wrapped string on them as well. You can recycle the metal at a recycling centre or scrap metal dealer. Or, you can creatively reuse the guitar strings and create something you or a friend will enjoy for years.
Use the wire cutters to snip off any cloth portions from the guitar strings and throw them away. Take the metal to a local recycling centre, most of which accept metal. Or, call local scrap metal dealers and ask what kinds of metals they're currently accepting. They will often pay a small fee for metal -- though since it's by the pound it will be minimal for guitar strings.
Make a necklace out of an old guitar string. Poke a hole near the top of a guitar pick and string it onto the guitar string. Use a safety pin to hook together the loops on both ends of the string.
Donate full sets of used guitar strings to the Second String Project. They donate used guitar strings around the world. Since guitar strings usually lose quality of sound long before breaking, a used set can still play for years. For people without access to new strings, it can mean the difference between having a working instrument and having to save up for a set. E-mail the project administrator at firstname.lastname@example.org, or mail sets to the following address:
28 Ladd Road
Ellington, CT 06029