We have always used MEK to clean the shafts, and I use a Q-Tip to clean the base of the vane before applying the glue. I use Flex-Fletch vanes and they do seem to have an oily residue left over from the manufacturing process. With Goat-Tuff glue, those babys are on there good.

Use caution when working with MEK, it is highly volatile, and you should have plenty of ventillation and solvent proof gloves. It will absorb through the skin, and makes you feel like crap for a while.