What's the best way to pull out fillament from an all metal print head Since retractions above 4&nbsp;mm can cause jams due to plastic sticking to the cold half of the metal print head, what's the best way to avoid jams when swapping filaments? 

Cool down and yank out, rapid pull out while melted, pull out at partial heat but not completely melted, or something else?
Cold/Luke-Warm pulling can cause damage and wear to the hot end, and should only be used in cases where you suspect there's a jam in the nozzle.

Pulling the filament out at a few degrees above its normal printing temperature and pulling quickly is what I use, and what I've seen other's also say, and the procedure most machines use.