I do also love ESSR,
As for using IG inks... I do not make a distinction between inks, juts use them (except for not mixing BSB).
I like to switch colors, so whenever I empty a pen I always flush it with tap water (as khalameet, water quality is very good here). Yet...
In ye goode olde tymes , those of (almost) one person-one pen , when I was a student, I would use one bottle of ink to the bottom and only when I switched bottles would switch colors, in those fast note-taking times, I wouldn't even clean the pen between refills from the same bottle, just refill and go on. I only cleaned it when switching colors for obvious reasons, and some times if the colors were close not even then. And of course pens would rest unused for the long summer holidays and dry out, which I would solve by straight refilling from the same (only one I had) bottle which had also rested unused.
I should say I never noticed clogging problems no matter what pen I used. Maybe I wasn't aware or was too tolerant (or I didn't know any better, who knows, those times are long gone).
Even with BSB, now I just do a (somewhat more thorough) flush with tap water and go on.
Maybe it was due to the pen manuals which recommended flushing the pen once a year except when using permanent inks, which required a flush twice a year. Maybe modern pens are more fragile.
BTW, you may find interesting reading current Montblanc user manual (go to page 14). They recommend cleaning your pen each 3 months, or if it had dried or clogged or had flow issues, using plain lukewarm water (and no flush fluid). No mention of cleaning after each emptying, using distilled water or any other such. I can see where very strong water may not be advisable, but I always understood plain tap water every (long) so was enough. And, as mentioned, it has worked for me for over almost 50 years.
Indeed, I do feel uneasy leaving a section on water overnight, which I have only done when cleaning a pen left unused for years that had been forgotten with a full load of ink (or a full cartridge) that -obviously- dried out, and only to make sure it washed out clean and new ink would not be horribly color contaminated (oversaturated, actually) by the redissolved load of dried old pigments.
Now, all that is my own, limited, barbarian experience which I produce in the hope it may dispel what I perceive as too strong (panicking?) fears, but I may as well be totally and utterly wrong. Take it with a load of salt. YMM(strongly)V.
Edited by txomsy, 25 June 2020 - 07:47.