How to reset waste ink pad on Brother DCP 770CW

How to reset waste ink pad on Brother DCP 770CW
Solution for "Error 46 Unable to Clean":

• Enter machine maintenance mode. FAX models with numerical keypads: Press the Menu/Set, *, 2, 8, 6 and 4 keys within two seconds. (if you fail to complete the correct key sequence within two seconds, press the Stop key to try again).
  Other (non-FAX) models: Press the Menu/Set and Black Start keys. Next press the “up arrow” key four times to enter the maintenance mode).
• Press the 8 then 0 keys in the initial stage of the maintenance mode to call up the machine’s log information list (function code 80).
• Press the Black Start key several times to scroll through the log information list to reach the purge counter. The purge counter is the 25th item in the list.
• Press the 2, 7, 8, and 3 keys in this order to reset the purge count to zero.
• Press the Stop/Exit key to return to the initial stage of the maintenance mode.
• Press the 9 key twice to return to the standby state.