Brother DCP-8020 - Manual (Page 257)

TROUBLESHOOTING AND ROUTINE MAINTENANCE 14 - 32
Caution
To prevent damage to the printer from static electricity, do not touch
the electrodes shown below.
3
Hold down the lock lever on the right and pull the toner cartridge
out of the drum unit. (See Replacing the toner cartridge on page
14-24.)
Discard the used drum unit according to local regulations,
keeping it separate from domestic waste. Be sure to seal the
drum unit tightly so toner powder does not spill out of the unit. If
you have questions, call your local waste disposal office.
Lock Lever