Don't drink from the cup!

If you got the drinking cup with the FFXIV Collectors edition, don't use it!  Well apart from drinking water from it, anything else is bad news.
If you read the piece of paper that comes with it, it says the following:
"Do not fill the product with the following materials as they may cause damage: Items including salt and solid materials, carbonated beverages, milk or other dairy beverages, fruit juices, etc."

Source: Kotaku