Buy the needle top cap. It makes it so easy to prime cartomizer without overfilling or getting liquid down the center hole. Caps also make refilling the tank a breeze! After priming cartomizer, take a few DRY (do not push battery button) hits. You will see bubbles coming up thru the liquid. This keeps it from having the burn taste because the cart is properly filled.You may have to do this during the life of the cart, but it is so easy, Try this. Believe me, I have been through all the pitfalls in the last 18 months. You will be amazed!