Lexmark Toner Cartridge, MS510/MS610, 20,000 Page Yield, BlackChoose Genuine Lexmark Supplies for Genuine Lexmark Results. Lexmark Return Program Cartridges Going green has never been easier. Recycle all your used Lexmark supplies is simple, smart and always free. Lexmark Return Program cartridges are patented print cartridges sold at a discount in exchange for the customers agreement to the license requirement that the cartridges will be used only once and returned only to Lexmark for remanufacturing and or