I would Heat the Hot-end up to ABS temperatures 240C ~ 150C
Push the filament firmly thru the extruder until about 30~40mm of filament have been extruded.

Allow the nozzle to cool then do another cold pull, examine the Hot end parts clean the nozzle.
If you have nozzle cleaning drills or replace nozzle they are consumables.

Even though I have a Teflon lined throat, still have problems as my hot-end was incorrectly designed.
So I added a heat cooling half round fin about the heater block and applied a cooling fan.

Hot End Cooling.jpg

You can see in the Image I re-designed the Parts fan duct to also cool.
I added Half round 2 fin heat shield for my Teflon coated throat.

This helped to keep the temperature down and deforming the Teflon tubing inserts.
Before I was replacing the throats bi-monthly.