Problem with feeder

I wanted to start a new print...and out came no filament.  Normally I think I can handle this by give a little presure to the feeder. The filament might have been grinded.  But unfortunately I have done this a little to strong and now it seems the printhead is full of pla....  I think now I have to take the printhead apart...

I just looked in the Ultimaker forum and on youtube and found some interesting tips.  I could try first if I could  "change the filament". 
     I preheated the extruder to 210 degreeds and then tried to pull the filament out from the back.  But it didn't move.  Neither in or out it wouldn't move.

Then I read about the nozzle that is clogged and ways to repair this.  And about how to take the bowden tube out.  (pull the blue horse shoe away.  Then press the little white collet down and try gently to pull the bowden tube  out.   )

That was the idea.   Preheating the extruder to 210 degreeds. Taking the bowden tube out.  Then pulling gentle the filament out the extruder head.   This is what I did and it worked.   It was clearly clogged.  I cut of the thick part and sandpapered the tipp to a point  and put the bowden tube with the filament again into the extruder.  I started a testprint....and it worked.... The filament is flowing again...