This post is kind of a "prelude" to what's coming tomorrow - how to deep-clean a really messy nib and feed!
Here we go:
So, my theory is this: Ink (any ink mind you) can bring great harm to your pen, if misused. The misuse that is the most deadly, is leaving ink sitting in your pen for lengthy periods, without being used. This type of misuse can melt feeds, sacs, and do lots of other nasty things. Here are some examples, shown below. These are all from different inks, not limited to one brand.
Take a look at the underside of this nib, as well as the tip of the feed. You will notice the nice thick caked-on chunk of ink sitting there! This pen was having "flow problems", and you can see why! Pens like these can be quite the beasts to get clean.
Here's a Pelikan M1000 nib, sent to me for a tune-up. Very nice nib, but it sure was dirty.
Take a look at the fins of the feed - notice how the back ones are clogged, and kind of fuzzy. Not good...
Here's a real good example. Take a close look at that feed, and you'll notice that the gold plating has transferred from the nib, and glued itself to the feed. This was one of the hardest nibs I've ever cleaned.
So the moral of this post is - keep those pens clean! It's very important that you don't let your pens be subject to having ink sitting in them.
If you are not going to use your pen for a while, clean it thoroughly, and dry it well before putting it away. That way, when you go to ink it up next time, it will still be working. :)