Recycling printer cartridges will reduce the plastic put into landfills. Most cartridges can be recycled up to six times and are guaranteed by most manufacturers to work as well as brand-new ones.
Laser-Tone International, (800) EARTH-58, will pick up and deliver back to you, for free, laser and ink jet printer cartridges and other office products you wish to recycle and reuse.
Eco-Office recycles and purchases used cartridges. They will provide lists of companies in your area that will purchase used cartridge, as well as companies that will provide remanufactured ones.
My contribution: I've got one to dispose of that I'll bring to my local community center so they can cash it in.