"I have had issues with several manufacturers' cartridges leaking oil from the threaded end. What, if anything, do you do to prevent this from happening with your cartridges?"
We've tweaked our post-processing and our coil intake design. Our oil is a bit thicker, which helps prevent leaking. Temperature and air pressure can affect any cartridge, so, be sure to preserve your W Vapes pens by resealing them in their protective tubes if you will be traveling in that sort of environment. As always, if you do have an issue with leaking, please return the device to your place of purchase, and we'll be happy to provide your vendor with a replacement.