Definitely clean the base metal and filler wire as best you can. Typically wire brush the base metal to remove the oxide layer. I'll take it a step further and wipe everything down with acetone. If you're still experiencing issues I would take a few passes with the AC balance set below 60 to provide...

Definitely make sure you are on DC, not AC as mentioned above. That looks more like contamination from either dipping the tungsten in the puddle or sticking the filler rod. Cut it off, grind it sharp, and ensure you're welding on DC.

Next best thing would be drill and bench grinder/ belt sander. Fast and produces a sharp tip.