After testing various nozzles, I discovered filament had seeped between the threads of the nozzle and heater block on the last change. I believe I performed the installations correctly following the instructions here: https://e3d-online.dozuki.com/Guide/Changing+Nozzles/45?lang=en I tried my best to remove what I could from this nozzle below with flush cutters and a heatgun and paper towels but there is still residue on it that I am unable to fully remove. I would say I've been able to clean maybe up to 50% of the contact surface area of this nozzle but I've been unable to clean inside the heater block at all given the internal geometry. Now that there is a permanent amount of PETG between the heater block and any nozzles I install from now on, I'm a bit concerned that this will negatively affect heat transfer performance. Should I be looking to get another heater block? Many thanks.