Printing ink and toner cartridges contain chemicals that are harmful for the environment and health. Many ink manufacturers provide free mailing labels to return used products for recycle and reuse at no cost. Please check the product's website if no such label is provided.
Local stores such as Target also offer ink cartridge recycling drop-off.
On the NIU campus, place used cartridges to be recycled in an envelope and address to "Campus Mail/Recycle."