The gag at any party

The idea is great and an eye-catcher at every party.
The blue lid dissolve very easily by the expansion of water during freezing, unfortunately it turns out to be a bit more difficult to take the ice glasses then from the red envelope. However, the tip with warm water by the previous speaker does this very well.

All in all, however, affect the cases fairly robust, even if they are only made of plastic.

A little tip on the edge: Assuming the freezer is large enough, can be 12 ice glasses "create" the day before and then store on the supplied tray in the freezer. Thus, the shape of an additional 12 glasses use and you have (if necessary) equal to 24 ice glasses at hand.