Canon S400 Reference Manual page 68

Notes on Handling BJ Cartridges
Storing the unused BJ Cartridges...
After you replace the BJ Cartridge with another one, always store the
unused BJ Cartridge in a BJ Cartridge container. If the BJ Cartridge is not
properly stored in the container, the ink will dry out and the BJ Cartridge
can no longer be used. Also, after removing the seal on the ink tank,
always insert it into a BJ Cartridge to prevent the ink tank from drying out.
Always store BJ Cartridges and ink tanks out of the reach of small children.
Caution
If any ink enters the eye or is accidentally ingested, seek medical assis-
tance immediately.
Using the BJ Cartridges 68