Why is myblu® cartridge stuck?
If you are unable to unscrew the blu® cartridge from the battery by hand, gently squeeze and turn the blu® cartridge with pliers. Do not use the pliers on the battery. Once you have release the blu® cartridge from the pliers, discard it immediately.
The most common cause for stuck blu® cartridges is over-tightening by the consumer. You should stop screwing the blu® cartridge into the battery as soon as you feel resistance.