I think refilling carts is too much work. I prefer to just drip a couple of drops directly on the atomizer. One thing I found that performs better is to take the filler out of the cart. I also take the two round things that have a pen size hole in them out of the carts. That way I can drip without taking the cart off of the atomizer. I just drip a couple of drops directly on the cart. This works great for me. Has anybody else tried this.