These pens were difficult to clean. Well, not the Hongdian N7, that flushed just fine but it also still had a little ink and wasn't dried.
The two Preppys and the Plaisir were completely dry. Flushed all I could with the bulb syringe (a ton) and even 4 trips through the ultrasonic couldn't get the feeds completely clean, so they're soaking overnight.
All the converters had ink behind the plunger, too, but Platinum converters disassemble easy. I'll add some silicone grease.

An overnight soak and a couple more long trips through the ultrasonic cleaner and all the ink is out of the section/feeds.
There is some slight staining of the clear plastic on two of them, but not enough to be a bother. Not the feed itself, those are supposed to be blue (Preppy) and gray (Plaisir).
I added some silicone grease around the plungers of the converters before reassembling them, too.
I've stored all these for now, but knowing me I'll find an excuse to refill them soonish.

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