firstly, let's start with the observation of the collector of preppy:
1) it is detacted from the feed.
2) there are 3 outlets for the fluid:at the nib (big outlet), at the reservoir input and of course through the collector.
3) water goes into the collector through the holes in the feed.
secondly, what was being tried around the net:
1) forced screw : people tried to screw a screw into the nib inlet and force the collector out. While it worked, it destroys the collector.
2) pilers with oil: it works but it does leave marks for the untrained. at least that is for me. i almost destroyed one before calling it stop.
thirdly, the gentle method of cleaning without destruction:
what is required is importantly, to stop the nib outlet. while putting a nib in place will work, it does not work efficiently because the nib will allow water out. therefore the steps are:
1) flush out the majority of the ink first using the normal washing method.
2) plug a syringe with water in the nib end, and another syringe in the reservoir end. because now the nib end is sealed, the water from the reservior end will be forced out through the collector, thus cleaning the feed. do it a couple of times, and do it gently. big sudden gush of water will not help. be gentle.
3) there will be little droplets of ink left in the collector. this is the last step to clean it 100%. using your thumb, close the nib outlet, and using the syringe at the other end, slowing force water into the collector and release it when the water reaches that drop. do it a few more time. then repeat step 2 again to clear everything out again.
hope this helps.
(first posted in facebook on 27th Sep 2014)