Completely Clogged Micro-Swiss Hotend

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I have a Micro-Swiss Hotend that is clogged with ABS to the point that I can't even take it apart. I have tried soaking it in acetone, and heating it up and cleaning it. The ABS is is the heating block, nozzle, and the piece that connects the cooling block to the heating block. After I heated everything up to 285C, I used some filament to clean it out, but the cooling block and heating block wouldn't go back together, and more filament got stuck as I tried to print with the unaligned hotend. I the connector piece won't come off of the heating block. I soaked the connector, nozzle, and heating block in acetone for 18 hours, and only about 1/2 of the ABS is gone. Does anyone have any ideas on fixing it?

I had this issue two days ago, also with my Micro Swiss setup.
Also tried high temp, 270'C, to get things unclogged. This I wont recommend, nor do again, only causes burning of filament or something that turned into dark brown blackish gunk that sticks like hell siezing everything up.
My issue was starting with PETG, shortly after a ABS print. PETG is untouched by acetone and pretty much everything else.
I used a brass brush and scotch scrub(green dish-washing scrub materiel) and battery acid, undiluted. Repeated 2min dips and some scrubbing got everything shiny again. I was worried I might lose the aluminium heat block, but hoped to save the other parts. Surprisingly the heatblock did not dissolve away. I did keep close watch on it thought. The acid is key in getting the burnt stuff off.
The two small screws that clamp the heater had no issue going back in and doing there job, as the thermistor screw.
The heatbreak and heatblock connector was however not going back together, like yours it sounds.
I used a M6 tap to clean the thread in the heatblock, this removed a lot of gunk.
To reassemble I used a little bit of Nickel anti siezing paste this time. It is working fine, unsure if disassembly will be easier next time, but it should be.

I hope this info helps.

Also, if you are using the stock hotend cover to print ABS I would suggest you try my alternative design. It solved a lot of problems for me since the stock setup blows a lot of cooling air on prints with the heatbreak cooling fan (front fan). Getting rid of that cooling made for much improved prints with PETG and ABS.

Thanks for the information! I'll look into the ABS fan cover. So far, I have gotten a lot of ABS out, but there is ABS on the connector that keeps the connector from fitting the cooling block.

That connector is suppose to be Titanium, try the acid and elbow grease, did it for me. I also used a o-ring pick on the chunks in the beginning.
If on the inside a drillbit, drilled with a pliers works. It takes extra effort by hand, but difficult to damage the part that way, while using a electric drill may be easier, it has a danger factor.
Good luck.