My E3D v5 is acting up. Every now and then I get a very underextruded layer, followed by a very overextruded one. Could it be partly jammed ? If so, whats the best way to clean it ?
http://bukobot.com/nozzle-cleaning - you may have a piece of particulate at the tip that occasionally gets shoved out of the way.
But I don’t have any Nylon filament 
You can do it with PLA and ABS too.
I had that issue with mine. The mating surfaces between the break and nozzle had separated slightly and gotten plastic between them. I couldn’t get them to mate properly again so I disassembled them all and soaked on acetone for a few hours and cleaned with a wire brush. Reassembled and was like new
@Shachar_Weis “String trimmer” line is very close to nylon, readily available, and cheap. Would work well for this application.
@Carlton_Dodd it should work. The most likely problem is that moisture absorbed into the plastic would continue to expand and make the tip of the nozzle run dry while you were waiting for it to cool. I’ve seen this happen with taulman nylon that has been exposed to too much moisture.
Of course, it could also fail entirely. I once tried, just as an experiment, using a nylon zip tie instead of filament. Didn’t work at all.
Recently ask a similar question. Found out a few things.
My nozzle had indeed walked out a touch the small gap creates a lot of tension then compression in retract and extrude steps.
Looked for a manual way to clean my nozzles, grabbed my small MAP gas torch. The filament will literally crawl out of the nozzle. I clean all my nozzles once week this way now.
Lastly, I had tried a SS direct drive hobbed shaft. It was machined incorrectly and not perfectly round. Missing a quarter of the revolution.
This was all in one sitting. I love this hobby.
@Whosa_whatsis
I meant to use the trimmer line for cleaning only; not for actual extrusion.
@Carlton_Dodd I know, but high moisture content can reduce its ability to be used for clean-outs by causing bubbles of steam to form in the tip, making it harder to pull it out solid without breaking off. For best results, keep trying to extrude as you cool down until it won’t come out anymore.
I use string trimmer line. Works very well. Pushing it through wile the nozzle cools. Then wait until it’s around 100 C and pull it out.