Our cartridges can be refilled to a point. They are disposable and will degrade over time with use. To refill, unscrew the mouthpiece while holding the glass cylinder. Fill the cartridge using a dropper containing your vape liquid. Then screw the mouthpiece back on while holding the glass cylinder. Do not hold by the threading while unscrewing or re-tightening as this might permanently damage the cartridge. Do not over tighten the mouthpiece as this may damage the internal parts. Do not mix other vape juices with ours as they may not be compatible. The cartridges are meant to be disposable, but with delicate handling, can be refilled a few times.