I have approximately 40 laser printer on my network. As a result I go through a number of toner cartridges. What can I do with the empty toner cartridges? Some are name brand like HP, or Lexmark others are generic. I know it's not really good to refill the toner cartridges because it is good the have the photodrum replaced. Does anyone know of any recycling programs out their for empty toner cartridges?