Cut out the eye of the nozzle, attach a straw between the two with one facing upside down, you may have to experiment to find a straw that fits (if they have the male valve system you can just use a wd40 nozzle)
FYI the plastic inner where the ink is within a biro pen is a perfect fit, cut about 3cm off the end.
I noticed you said cut the eye out the cap - just take the two caps off and use the biro inner direct, a lot easier :)
I noticed you said cut the eye out the cap - just take the two caps off and use the biro inner direct, a lot easier :)