This might be a bit late in the day but I find storing in a dark place keeps it fresh so to speak.
All my makeup is kept in a drawer and I have had no problems this way, a friend of mine keeps hers out and in direct sunlight during the day (she didn't realise this as when she goes to work, it's not sunny out and I suppose you don't really take that into consideration when you're not at home) and her Fluidline semi melted and then dried up during the nights and was a horrible mess, she added some contact lens solution to it, shook it and closed it. That seemed to work.