I first started out cutting the dipped tungsten so the wod of aluminum was gone, then resharpened it. Now ,, when I dip the tungsten, I grind the wod to something manageable ,, grind it down to tungsten size and resharpen. I have not noticed if the tungsten "absorbs" the aluminum in any way. This helped save spending money on a lot of tungsten. When welding aluminum I sharpen the tungsten to a crayon looking tip with a flat end..kind of makes the arc come off the tungsten a bit differently than with a needle point. Just my observation.
gramps
That will usually work pretty good! I've done it myself. Just gotta be careful to not use too rough a grit of sandpaper so you don't accidentally turn down the tungsten diameter. Then just re-sharpen the tip about ½ a mm and you should be good to go. The tip is the hottest part, so if any part of the tungsten would absorb the contamination it would just be the tip (that you just slightly ground back anyways).