Brother MFC-9660 Owner's Manual page 156

For best performance, use only genuine Brother toner, and the product should be used only in a clean,
dust-free environment with adequate ventilation.
After you have just used the machine, some internal parts of the machine
will be extremely HOT! So please be careful.
Follow these steps to replace the drum unit:
1
Open the front cover.
2
Remove the old drum unit. Place the drum unit on an old cloth or large piece of disposable paper
to avoid spilling and scattering the toner.
HOT!
Troubleshooting and Maintenance
147