Chances are, if you are like pretty much anyone I know, you have a box or two of old power cords that you don’t know what to do with. Everything you order nowadays seems to include all the cords you would need, so the old ones pile up. So what do you do with all those leftovers?
First off, it is not the best idea to just throw them away. Most places have laws again improper disposal of electrical component. Electronics often have toxic chemicals, such as mercury and lead, in them. Cords can also be a hazard and should be disposed of properly.
The first thing I would do is see if any friend, neighbor or relative has a need for any of the cords. They may also have a big box, but maybe you have just the cord they have been looking for!
With all the cords you have left over, look into local e-recycling programs. These have become popular services in the past years, as a recent study has found the average household owns approximately 24 electronic products. Most of these places will also take the cords. Many have e-recycling events or permanent drop off locations. A great resource for this is Earth911 . By clicking on Recycling Search, and typing in Electronics near my city, I found many resources that listed cables along with other electronic devices.
Finally, check with some of your local electronics retailers. Most Best Buy  stores have a recycling program in store, as do others, and will accept the cords. Other places may take donations of your old electronics and cords.
Here are some resources for more information about the issue: