Waste toner gets full before toner runs out

Actually, the waste toner should get full sometime before the regular toner runs out in laser printers that have several toner cartridges compared to the single waste toner reservoir.

You can dump the toner reservoir out and avoid buying the empty waste toner 'reservoir.'

I did this on my Brother Laser printer and saved about $30 or so for an empty plastic waste toner bottle or jar.

If this is the way the Kyocera-4020DN is, then I would put the waste toner, which is just that, waste, and put it into a plastic zip loc storage bag and throw it away. Don't breath the toner.

Good luck on this repair.