Brother HL-3400CN Series - Manual (Page 164)

CHAPTER 5 MAINTENANCE
5-7
3. Release the Oil Bottle Lock Levers as shown below:
Fig. 5-5 Release the Oil Bottle Lock Levers
4. Remove the empty Oil Bottle from the Fusing Unit. Hold a sheet of
paper under the Oil Bottle and lift it out of the Fusing Unit. Move the
bottle away from the printer to the right, so that the oil will not spill
into it. Be careful not to spill oil inside the printer. It could cause
considerable damage to the printer.
Fig. 5-6 Take the Oil Bottle out