Clogged hot end nozzle

When I ordered a j-head hot-end, I was not able to specify the nozzle diameter and I got sent one with a 0.3mm diameter.  Combined with a power resistor which could not keep up, you can imagine how long each print takes. And if the heater could not keep up, there's a big chance you will get a plug.  I don't even know what kind of resistor it had in there but I already ordered a heater cartridge to replace it and see what improvement I can get to in terms of print quality and print speed.

During one of my early prints, I noticed that the extruder keeps springing back, but this time, nothing comes out of the nozzle anymore. I stopped the print and tried to push the filament but it wouldn't budge. The temperature looked okay so it must be a clogged nozzle.  When I removed the PTFE tubing and pulled the filament out, it was coiled inside. This happened when I pre-heated the nozzle and went to do other things.  Apparently, this is a common problem with j-heads and people suggests to put a fan to cool the upper end of the j-head.  This prevents it from heating the filament inside that makes it soggy.  When the filament gets soft, it will coil up and won't be able to push the filament down to the hot end.

Following their suggestions, I bought a fan.  I couldn't find a smaller one so I bought the 60mm. I'll use it until I can find a smaller one.  Here it is mounted on my printer.

The fan helped and I wasn't having a plug anymore until a few prints later, it happened again. It was for a different reason this time.  When I pulled the filament, I didn't see much of the coiling I saw before and after a closer look, I found this...

It looked like a seed or something and it was big enough to block the nozzle.  Once I cleared the clog, I was able to print again.  Too bad I couldn't continue the print and had to start over. I wish there's a way in the smart controller to go back a few steps so you won't have to start over whenever this happens.