Another thing to remember with your particular machine is that Oki created an internal waste hopper which is accessed through a small opening which opens when the main hopper door opens (by twisting the handle) - the important thing to realise is that you can't pour away the waste toner without sealing the main hopper door with tape otherwise when you shake out the waste toner, all the new toner inside will also pour out so the best thing to do before each refilling of new toner is to open the main hopper door, seal the opening with tape and then tap the waste toner over a bag and any waste toner will pour out. Once you are sure the waste toner is all empty you can then unseal the main hopper door and pour in new toner before twisting the handle to close both doors before you put it back into the machine.
Just one more thing to remember is that you can continue to print until the chip runs out and these are easily replaced by removing the old one (you'll find it under the blue sticker and beneath a small grey plastic door) next to the handle!