Toner is the dry ink powder used in laser printers, fax machines and copiers. These machines generally accept toner cartridges, the replaceable, removable source of ink toner. Toner refill kits can also be purchased, allowing individuals to refill and reuse toner cartridges. Toner cartridges can be divided into three categories: OEM cartridges produced by the same name-brand company as the printer/fax/copier itself, compatible cartridges made by lesser known manufacturers but sold at a fraction of OEM cost, and remanufactured cartridges. Most manufacturers have environmental policies in place, allowing for free shipping of cartridges back to the OEM where they will be cleaned, refilled, and reused.