i got this of an online manual i hope it helps
* Avoid temperature extremes. Whenever you can, store your fuel in an environment in which the temperature is fairly constant. Frequent heating and cooling causes moisture to condense inside the fuel bottle, and excess moisture spoils nitro fuel.
* Keep the fuel bottle off the floor. A concrete floor will chill the bottle and can cause the moisture inside it to condense.
* Cap it! If your jug of fuel came with a plug under the cap, don't discard the plug; use it whenever you put the fuel away. You'll have a more effective seal than if you use only the cap. If your fuel bottle is flexible enough, squeeze it before you tighten the cap to expel air-less air, less moisture.