Imagine that you go to a university which has ~55,000 students, including maybe ~1,500 Jewish students.
Imagine, also, that you're male. Therefore, you're required to spend some time studying Torah.
Outside your university's free store, there's a free library. It's much more informal than the school's official library. There are several bookcases. Anyone can donate books or take free books. The books are almost all about secular subjects, such as business, anthropology, environmental science, and others.
When the free library gets too full, you might want to volunteer to weed it. You discard old and/or damaged books. Weeding can make room for newer and better books. (Source.)
All libraries must be weeded, or else they might end up packed full of outdated and unwanted books.
You might volunteer to weed the free library once a year. You might spend a few hours, or more, on the weeding project.
Perhaps this weeding project is a mitzvah of chesed, which helps your fellow students to access recent, undamaged free books. Or perhaps it's a waste of time, which could have been better spent on Torah study. Which view is correct?
If possible, please provide answers from a Modern Orthodox perspective.