Oki C130n Instruction Manual page 74

Important!
The maximum storage temperature is 35° C (95° F) and the
maximum storage humidity is 85% (noncondensing). If the toner
cartridge is moved from a cold place to a warm, humid place,
condensation may occur, degrading print quality. Allow the toner to
adapt to the environment for about one hour before use.
"
Always keep toner cartridges level when handling or storing them.
Important!
Do not hold, stand or store cartridges on their ends or turn them
upside down; the toner inside the cartridges may become caked or
unequally distributed.
"
Keep toner cartridges away from salty air and corrosive gases such as
aerosols.
74 - C130n User's Guide