Sad times, my J-head MkIV B seems to be blocked,

Sad times, my J-head MkIV B seems to be blocked, has anyone here taken one apart before?

Not that one, but the ones I have taken apart, I got the metal extruder part by itself and put it on a hot plate to get the guts cleaned.

I have. Once you get the tip off use some acetone to soke it for about 20min yhrn your plastic will come out (if your using abs) then stick a thin wire in tip to push it all out. If you have pla stuck just heat up the t to abs temperature and extrude or maybe put a wire in the tip. It happens to me kinda ofter when I print with black abs because its not very pure