How to reset Brother MFC Series printer

Problem: Brother MFC Printer display "unable to clean" or Error 46
Solution: 

• First turn of the printer
• Switch on the machine while holding down the “menu” button until all the leds are flashing on/off. Now you are in “maintenance” mode.
• Press 80
• Press the “mono start” button several times until you see “purge: xxxx”
• Press “2783” in order to reset the purge counter. You will see: “purge:0000”
• Press the "stop" button.
• Press “99” to exit the maintenance mode.