I have been enjoying the volcano setup on my CR-10 5S for about a month now. I have a few projects that I want to print foodsafe, so I picked up a stainless 0.4 nozzle by microswiss and started printing some test items with some Hatchbox PETG which I keep in a drybox. All systems were go, so I embarked on the first more serious print, which ended up running about 16 hours. By the end of the print, I a little PETG oozing out of the top of the heater block. When I tried to unscrew the nozzle, it was clear that PETG had crept its way into the threading. Not good. I started by heating the nozzle to around 90c and started pulling the bigger gobs of PETG from the aluminum block. Most of it pulled off pretty cleanly at that temp, but it was not enough to get the nozzle and heat brake off. I increased the temp to about 120c and managed to pull the nozzle and heat brake free. The microswiss had a thin layer of PETG all the way down the threading, however on the heat brake, it appeared to be clean where it meets the nozzle- let's call that the bottom. The bigger surprise is that the "top" of the heat brake- where it comes out of the heat block also had some PETG. I am not sure what to make of this, because there should be PETG running all the way up... Here's a link to an album In the process of removing the heat brake, My pliers slipped, and I roughed up the threads, so I think that's the end of that heat brake. It won't smoothly thread back into the upper heat sink, so I ordered a replacement, and will probably just bin the heat brake. The heat block has a little bit of PETG inside where the heat brake meets the nozzle. I am considering hitting it with a butane torch and maybe getting a Q-Tip with alcohol to try and swab that little bit out. If I fail, I did order a replacement heater block As to the microswiss. The threading is all fine, but it's horribly coated in PETG. I would love to save it if I can. There seems to be little to no solvent based fixes here, so I am not sure if there are any clever ways to get this threading properly cleaned. Bear in mind I had made a real effort to seat the nozzle properly. I had printed for a few weeks with the 0.6 brass nozzle, and it worked beautifully. The nozzle switch was a complete non issue. The brass came out clean as a whistle. The stainless went in perfectly, but clearly something happened during the longer print. So as you read and look at the photos could you all please weigh in on what might have gone wrong here? I essentially had to replace half of the E3D setup, and may be purchasing a new stainless nozzle. The $60 or so I spend this one time kind of sucks, but I really would rather not end up in this situation again. What can I do better? Is it possible there was maybe a bit of a flaw in the microswiss nozzle? Perhaps I should have tightened the heat brake into the heat block a little more? Any feedback would really be appreciated.