Actually, taking the argument to the extreme, any ink demanding cleaning would be inflicting a "damage" to the pen. If we take the argument to the extreme, then say, a piston filler, should wash out clean of any remnants of ink after all the ink has been used up in writing, and end up pristine, just as new (kinda those TV ads where the pan is turned to drop the contents and it stays clean). Taken to the extreme, if you need to wash/flush the pen with water, then obviously it is because it has been damaged (it no longer works as new for filling with a different ink without staining it, it is damaged).
That's what a naïve user might have expected 50-60 years ago (if s/he hadn't known better): buy a piston filler, fill it, use it, no remnants, fill it with a new ink, use it, etc... this naïve user would have sooner or later noticed that when switching inks, the new ink might come out contaminated with the old and protested it was a malfunctioning pen or ink. Bindeardondat. Maybe, in those old years when nobody cleaned their pens, that person would have left it for long periods unused. Maybe the ink would dry in... which obviously would be a failure of the pen. Maybe at some point the feed would be clogged...
It is not so uncommon to get vintage piston fillers with dried ink inside. Till now, all it has taken me has always been to flush them with plain water. Silly me, I didn't know they were damaged and I should have returned them. Pens are for ink, not for water. And if you need to put water in it to remove that nasty thing inside the ink window, then it is obviously damaged.
But wait, it gets even more interesting. Some inks are quite acidic or basic, or so I have been told. Many had phenol, surfactants and detergents to improve flow. One even had something called Solv-X. In the old times, they might be formulated with wine, tea or other components. However, if you flush them putting any other kind of non-neutral pH fluid, then that is surely bound to damage the pen as well, isn't it? No one would suggest putting anything but ink inside the pen unless insane. Not water, and certainly not soapy water, solvents, or a diluted solution of very mildly acidic or basic products like vinegar, ammonia or bleach. Those would utterly destroy the pen. Sure. Just look at what they do to plastic bottles or washing machine conductions. Crazy. Can't imagine how anyone would dare suggest such a hideous thing.
DISCLAIMER NOTE: do NOT do it unless you know what you are doing and if you do not feel confident, avoid it. Some materials may indeed be affected by chemicals (including water), humidity or its lack, temperature, and whatnot. Always make sure you know what your pen is made of and what it may stand. Ditto for any ink you use on it. And if you fear the ink may damage your pen, do NOT use it. That is what disposable ballpoint pens and computers are made for.
My deepest apologies for any irony. I hope no one feels offended by this exercise. I do not know what has crossed my mind. Even though I had my tin hat on, some weird radiation must have affected my empty skull (for, I can guarantee you, mine must be empty or close to) to make me write this. So, please, consider my stupidity and discard my message as the ramblings of a crazy old man. You can't go wrong if you ignore me, but you can if you take me seriously. Just check the facts for yourself.
Edited by txomsy, 16 December 2019 - 16:09.