Cloudy when cold, Mathmos Turqouise/clear.

[Ouija]

Just wondering if any of you guys are eperiencing this? I never noticed this before, but recently, my turqouise and clear Astro is cloudy when it is cold, and has a slight film at the top of the liquid. Don't get me wrong, it's not a bad problem at the moment, as soon as it heats up it is crystal clear again.

I just hope its not something that will get steadily worse with time.