Is it though? I definitely had teachers in middle/high school with oddball requirements like “only physical books more than 10 years old are valid sources”. Total nonsense but it does happen. College is a place where you are meant to have these bad assumptions challenged and corrected. Presumably after a response they’ll be better for it.

I don’t think I’d use them for anything other than their intended purpose if you don’t know exactly what’s in them. For the leaky ones, you could probably collect the gel into some other sealed container like an old jar (not totally filled). Then it would still work well as a cold source for coolers/lunch packs.