I refill mine with CASH liquid as well and after vaping with that stuff I didn't want to go back to those flavorless stock carts either, so this is what I did: I took my remaining new carts, blew threw them from the battery connector end until I had blown almost all the liquid out of them. Then I refilled them with the CASH liquid. Any liquid left in the carts after blowing them out didn't really affect the flavor of the CASH liquid because the stock cart flavor is so weak to begin with.
I also have a Pilot on the way from Puresmoker, and I can't wait to get that thing in!
AACK! WHY DIDN'T I THINK OF THAT!?! It never even occured to me... massive thanks for the suggestion!
I don't think I'm really disappointed with the Magnum itself, I've just realized that refilling is very important and that is not so easy with the Magnum carts... on the other hand, the one I refilled has outlasted the battery charge, so that may be a plus.