For most ink+pen combos I'll use water to flush the ink until the rinse water's clear, then either fill the pen if has an integral reservoir (e.g. sac, piston, ED) or if a c/c let the section soak in water for perhaps an hour, then see what if any ink remains by emptying the pen of soak water onto a white saucer, then do another water flush.
For ink+pen combos that are tedious to cleanse, after most of the ink was removed I'll use a DIY cleaning solution to expedite things. (My Tedium Tolerance is diminishing.)
When I start with a new ink, I'll do an 'escalating' clean-up, checking the rinses to see what if anything was left behind. I'll start with plain water until I'd usually consider the pen to be clean, then do a thermometer flick or maracas shake to remove most remaining water; then give the pen a soak+flush with the pen cleaning solution, then rinse until I'd consider the pen to be clean; then give it another round using a technical pen cleaner, such as Rapido-Eze.
> That approach revealed that some inks can leave a residue after plain water, and after a 0.5 - 1.0% ammonia + surfactant.
> Emptying the soak water after each stage onto a piece of white paper, then letting it dry, will give a better idea than using a white saucer to see what's left in the pen after each stage.
The ultrasonic bath is used mostly for jewelery and used pens found in the wild or if I've used a persistent ink in a Parker 61 or if I don't want to use aggressive chemicals (on vintage pens.)
I tend to avoid removing the nibs from the feed, but if I thought there was persistent inky residue, I'd give them a whirl in the ultrasonic.
When I learned that a dilute acetic acid solution would remove IG ink residue that ammonia-based cleaners leave behind, I tried that in my pens which see a lot of those inks, but nothing visible was released. So either my pens had no such residue or the residue removed was not visible to the unaided eye.
See also 'Limit to Soaking?' http://www.fountainp...king/?p=2453755
Edited by Sandy1, 10 May 2014 - 09:49.