If the cartridge is completely empty, you may put it in the trash.

Check with the store where you purchased the cartridge or any office supply store - many offer refill and recycle services. Look at the instructions in the box of your new laser or ink jet cartridge to find out how to recycle your old one. Many companies will provide instructions, packaging materials and free postage if you wish to recycle your old cartridge, which is then refilled and used again.