When getting food and drinks from Joe's (and ideally other university retailers), there should be the option to buy a (more expensive) reusable takeaway container, which you can then bring back for a refund (which could be paid directly or could be in the form of a discount on the next purchase). This will improve student wellbeing by allowing food to be taken away without an uncharge and will be good for the environment by minimising the use of single use containers.