I use insulin needles and lemon juice too, but I've also heard something about injecting a hypersaline solution or calcium. Supposedly it's safer for the rest of the tank, but I've never done it and can't make any statement about the effectiveness of anything other than the lemon juice. My only complaint with the lemon juice is that it damaged a couple of nearby zoa heads the last time I did it. Maybe I was just overzealous, but based on how the crafty little booger had hidden in the middle of them, it was probably unavoidable.
Good luck getting rid of all traces of the little POS -I know it seems interesting now, but if you disregard everyone's advice to annihilate it now, we're sure to read a post from you in the future about how they've taken over your tank.