I don't know what kind of atomiser you're using, but here is what I do with my 801. This works for cleaning dirty atts or for getting rid of the old flavour:
Use 110 Vodka or Everclear. Put your finger over the batt side and pour enough in the cart side so you can shake it. Then put your thumb over the cart side and shake for a minute or so depending on how gunky the atty is. Then rinse in plain water, blow out from the batt side and let dry overnight. Good as new.