Hi Ken, the white plastic tubes I assume are PTFE tubing, which is heat resistant and is most likely used to go into your hot end nozzle to align the filament, but you probably already have some in there if they are spares.

If the filament is not feeding through the other extruder, its possible there is still some gunk in there, I would heat it up really hot to like 250c, 260c and see if that melts the factory testing goop out of there.