A little PVA stuck in print head

[Joymaker]

I printed with a cut strand of PVA for support material. The PVA ran out during the print. BAD IDEA! I wound up with a length of (somewhat burned) PVA stuck inside the plastic tube that leads to the printhead.

Using a candle for heat I got most of that out. But there's just a little residue left. I've got one of those cleaning kits from ebay with the little fine wire- and that wire will not go through the .4mm hole by any persuasion! Nor will any light.

Now what? I'm soaking the head in acetone overnight. Other ideas?

[Alibert]

As the PVA has been carbonized, the carbon will not dissolve in organic solvents. Actually, don't use acetone as any PVA residue will dissolve easily in water. You may be able to loosen the residue (if there is still some PVA left in it) by boiling it in water with a little dish washing detergent added. Rinse and dry thoroughly aftwerwards. If you have an ultrasonic cleaner, you could try that as well, it might shake stuck carbon particles loose.

My suggestion would be to exchange the nozzle and ptfe tube for new ones. It does not cost that much, and quickly outweighs any cost in losses of failing prints in the future due to remaining small particles dislodging and clogging the nozzle. It is wise to just order spares from china anyway to have them in stock. There is no rocket science in a brass nozzle or a piece of PTFE tube, and those few bucks will save you a lot of grief.

[Joymaker]

Well, I did both of those things - acetone, then boiling with dish detergent. However it worked, it worked, and I was able to get the cleaning wire through. Thanks!