Brother GTX600NB Instruction Manual page 219

(4) Remove ink clots, if any, protruding from the nozzle surface on the underside of the carriage.
Nozzle surface
Ink clot example
<CAUTION>

When removing ink clots, do not use hard objects like iron tweezers. The nozzle may be damaged, resulting in non-ejection
if the objects touch the nozzle or other parts.
Use gloves and remove ink clots by pinching them with a clean stick or your fingers.
Precautions to keep good printing quality/use printer over the long term
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