There are a few situations in which a cartridge may leak you should be aware of:
Sometimes, factories may overfill ink cartridges. To be safe, we recommend opening your cartridges over a sink or garbage can to avoid any messes a potential leak might create.
If a cartridge has been in an area of high temperature for a period of time, you may notice the ink bubbling or dripping out. This happens when the heat creates a pressure vacuum within the cartridge, and that pressure blows the ink out when the cartridge is opened. If this is the case for your cartridge, put it on a paper towel and set it in the fridge (never the freezer) to cool for a couple of hours before installing it to use.
Sealed cartridges may have a pressure vacuum inside, meaning once it is opened, it may leak ink as the internal pressure of the cartridge balances itself. The cartridge will still function just fine, but it will need to sit on a paper towel (print head down) for a few minutes before installing.