I bought a Parker 61 capillary filler fountain pen and pencil set that looked like new. (I wrote a brief post about this back in June 2014.) Even the silicone coating on the filler system is perfect with no flakes or scratches. However, I couldn't keep it writing; the flow was so dry.
No doubt it needed to be cleaned well, but I'm not willing to risk taking it apart after reading how easy it is to break them. So, I've flushed it out with a bulb syringe several times and refilled with different inks to try to improve the flow. This has only been partially successful and has improved marginally by using increasingly wetter inks. Until recently the best ink combination for this Death Valley dry writing 61 was Waterman Serenity Blue. But even that was not a great solution - no pun intended. Obviously there must be some residue blocking the flow that I haven't been able to clear out and I was about ready to give up on it.
However, recently I was reading about intense blue inks and ran across a review of Levenger Cobalt Blue in which it was noted that one of the problems with this ink is that it bleeds and feathers so badly because it is such a wet ink. Since I have a bottle of Levenger Cobalt Blue, I knew this to be true and was the reason why I stopped using it even though I love the color. Then it dawned on me that Cobalt Blue might be wet enough to flow through my Parker 61. So, I cleaned it thoroughly with the bulb syringe and after expelling all of the water, I dunked the Parker 61 filler into the Cobalt Blue ink.
Afterwards, I tried writing with it and there was no ink flow at all. Out of frustration I put the empty syringe on the end of the filler to see if any ink was in the pen, because I then wondered if the capillary system wasn't picking up any ink. I squeezed it and ink came out of the nib. So, I dipped the filler back into the ink bottle and then reassembled it to try it out. Amazingly, it wrote the best it ever has so far. It still is a dry writer and feels a bit like writing with a soft pencil, but not as dry as it had been in the past. The next morning I took the cap off to try it again thinking it will surely have stopped flowing or skip as it has in the past. Instead, I was pleasantly surprised to find it still wrote just as well. The next day it is still writing easily with no skips, drag or false starts.
While this doesn't completely solve the partial clogging, it at least has the pen working at an agreeable and very usable flow. It is funny that an ink and a pen - both of which I had given up on - have turned out to be the perfect combination!