Disclaimer: I've only done this once, but it worked pretty beautifully the time I did try it. Proceed at your own risk.
User fancybiscuits says:
Toner kills vacuum cleaner filters, kills them dead
Printers are extremely complicated machines we often take for granted. There are quite a multitude of ways printers can go wrong, one of which is waste toner not correctly collecting in the waste toner bin.
Instead of wiping off the toner, which can potentially stain whatever you are wiping, try using a vacuum cleaner with a tube attachment to vacuum the mess. Vacuuming avoids the smudging the toner and can reach many nooks and crannies in the labyrinth of printer parts. Be careful not to vacuum up non-waste toner from the surface of the drums (the metallic cylinders) in order to avoid trashing unused toner.
Remember that toner is not very friendly to the environment! Be sure to dispose of it in your eco-friendly method of choice, whether that is putting it in your waste toner container or some other way.