Not sure which one the v3 is but I have bought the exact same model as this
vision ego start kit.
With mine I was able to remove the top, remove the tip and soak it in water. Then I flushed it out by filling it up with more water and shaking it. Then follow all this by a dry burn to get the rest of the gunk out. Eventually this worked and got the flavour out.
I used the Fireball flavour from Ginger. Lets just say that even though I got the flavour out. I have a set atomiser and
tank purely for this flavour as it taints anything you put it in
