We invented a new way to clean the PLA residue which clogs the nozzle. The instruction is attached as the subtitles. Please turn them on while watching.
This is very cool but does not help me in my newest problem: a glob of melted PLA forms above the heated area in the tube near the top connection. No amount of heating will melt it and I often have to forcefully push it down into the heated area with a metal (brass) rod. This is happening in the middle of prints when a glob will clog the upper extruder module and needs petty harsh force.
how about using oil ?
They call this the "atomic pull" in other printing circles. Basically, melt filament into the nozzle, and pull it out when the plastic is a bit cooler and more solid. It's a handy trick when you're changing colors or materials.
It's also called a 'cold pull'. I've done it using either of the filament load or unload functions to heat the print block, but this is a little less annoying than dealing with the filament getting run in or out while you're working the hotend.