Our Creality Hi recently had an issue with the push-in PTFE holder at the top on the print head. The sprint steel in the part broke apart and needed replacement. Instead of replacing the entire extruder feeding mechanism, we were able to slow pry out the damage push-in and replace it with another one from an old upgrade kit for the Ender 3. When inserting threading in the replacement part, we heated the plastic up with a heat gun and then screw the part in. Once the part was in, we waited for the assembly to cool down.
Sometime after the issue was resolved with the push-in, we ran into an issue with a clogged nozzle. We tried multiple times to do a cold pull to clear the nozzle, but the clog persisted. To try and clear the nozzle, a tool, 2827-260A-ND, was used with a point that is slightly small than the 0.4mm nozzle.
The nozzle was heated up and then the tool was inserted into it and then removed. A new piece of filament was then inserted and another cold pull was preformed, this time clearing the clog. The culprit was a small piece of spring steel from when the push-in failed.
Above is the piece that clogged the nozzle and resulted is failed prints.