So you have a nice reprap 3D printer and you use a Merlin HotEnd. Yep, those are fine, until they clog. And when they do, be EXTRA careful with the nozzle. If you are printing with ABS, some ABS juice will fuse the nozzle and the body part, and since the nozzle is extremely thin, any excessive force (don’t even think about using plier, I broke mine with my fingers, nice and clean) will simply cut it off.
If you are lucky, unlike me, you can still remove the threaded part with a pin or a needle (heat it slightly) and find another nozzle.