Error 46 in brother mfc-440cn

Machine Error 46 ("Unable to Clean") indicates that the wasteink is full. Basicly it gives you two options - have it replaced (a semi-complicated performance which requires buying a spare part and change it yourself) or have it sent to service. If you do not have any warranty on the machine, the more suitable would probably be to just replace the machine instead, since it's relatively cheap compared to both service costs and having the wasteink replaced, but you instead get a full new warranty on your new machine.
Unfortunately, there's nothing you yourself can do to remove this error, without actually changing an item inside the machine.