Keep it in any cool, dry, dark place. Not sure about using a freezer or fridge though. Enan sucks to work with, i have tried freezing it the night before to work with it, but no matter what i lose some. Now i always warm it till its all liquid and squeeze it out a small hole.

put it in the frig til you ready to work with it. then its a solid. plus whatever you have (100g or whatever) make one big batch and you dont have to worry about it. just dump it in the beaker.