Repairing a pen

Some tips to repair a ballpoint / gel pen which still has ink but simply refuses to write:

• Scribble circles on cardboard
  
• Simply draw a few circles on a glass surface
• Heat the ball point for a few seconds over a small flame (eg. cigarette lighter)
• Swing the pen in an arc a number of times to force the ink to the tip using centrifugal force
• Scribble a few lines on a rubber surface

Source: Wikipedia

Have yet to personally examine these methods. Have lots of pens which are like that >.<

If you have tried before, please tell me which method works best! =)