Well, after much searching and ordering and having orders cancelled it seems my pockets just aren't deep enough for new prechambers.
Apparently they're now made from unobtanium and the shipment from Pluto is indefinitely delayed until it's planetary status is resolved.
So, I'll be removing the five prechambers from the "parts" NA 300D which is low mileage in hopes of getting four serviceable units for the 240D. To that end I'd like to thoroughly clean them and was wondering if y'all had experience with any type of solvent that would remove the soot in a good soaking. You know, something like the good ol' bucket of carb cleaner that the EPA deems useful only for making Chernobyl smell better. I don't have access to an ultrasonic so it's gotta be something I can just soak 'em in, even if it takes a week!