Oki C5850 C5950 CMYK 8K Black & 6K Colour Cartridge Reset Chips - BRAND NEW PRODUCT!  Ref: 3670
The easiest way to refill these cartridges is to put some sticky tape along the main hopper door so when you turn the toner cartridge on its side and you push in the waste door trap door to pour out the waste toner you don't lose any of the new toner inside the cartridge. If you hold the cartridge vertically using the handle waste toner should pour out a small door at the other end of the cartridge (if you use a small pencil to tap the end this will ensure all the waste toner powder pours out of the cartridge) Dispose of this waste toner into a plastic bag before turning the cartridge upside down again at which point you can remove the sticky tape and refill the main hopper with fresh toner powder. Remember you will also need to exchange the reset chip which can be found above the handle under a small plastic door before returning the cartridge to the drum to continue printing!