I brought in unopened sodas and candies. As long as you don't bring in glass bottles and liquor, you should be fine.
You can bring in soda water sandwiches as long as the bottles have not been opened and plastic and in a clear bag
If you decide to bring something in, use a clear bag. That way you don't have to empty out your bag. And yes, the list of acceptable things to bring in is long.
That would be a pretty long list. Is there some things more specific you want to bring in?
Empty water bottles (they can fill your bottles if needed) and your own snacks.
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