I don't really have success with cleaning cartos either. Best way to try juices prior to dedicating a cartomizer to it is by dripping. Did you purchase a drip tip? If so, just screw the atty on, put on the drip tip and drop 3-4 drops in, give it a sec, then vape away. If you taste a burnt flavor, try dropping 1-2 more drips in. Attys have to stay wet, but too wet and they gurgle, takes a little practice but you'll get it. There may be a YouTube video on it.
*Droid
*Droid