@denke, @T3P3Tony, @Dino,

Thanks for the cogent replies y'all... : ))

Well, I'm sure I did it wrongly, and it looks a bit a messy but eventually I was able to unclog by accidentally employing the 'cold-pull' strategy, as everything else I tried ended with poor result. My fully customized kossel (was originally an AnyCubic, but none of the original parts exist yet it occupies the same physical space), employs a Bowden tube with a frame mounted 'extruder' driver located about 650 mm distance from the efffector. I can see the value of a direct drive in some instances.

I unhooked the Smart-Effector, and unscrewed the nozzle. I heated it with a hot-air rework tool. I pushed an accupuncture needle through it and it came out gooey but didn't unclog. After fiddling around for a time, I let it cool down, then reheated slightly, then pushed in a small length of PLA, let it cool down a bit and then was able to pull it out. That worked.

However, I chose to replace that nozzle it with a new nozzle. It was the nozzle that was shipped in the original AnyCubic kit of parts. I did not want to use the new authentic E3D-V6 hot-end nozzle for testing and calibration. The AnyCubic nozzle had crashed into the table many times over 18 months. So at least one part of the AnyCubic was useful, afterall. I learned a lot on that printer, I couldn't get it to work as a printer, but it was useful for learning how not to do things.

So now I'm in the market for good quality nozzles, there are many being hawked by vendors, such as, --stainless steel, titanium, ruby tipped ($400 ea), chrome plated copper...yada yada yada. When I have a better feel on things, I'll upgrade to something better than this bag of 0.4mm aperature brass units that some vendor sent me a while back. But I'll go through them first.

3mm