Deleting Diary Entries

In preparing for the new school year, I have deleted and/or moved all students to their new classes. However, last year's diaries entries are still there. How do I delete them? I presume they are unnecessarily using up memory space,

Hi Suzan,
You shouldn't have to delete diary entries. It doesn't take that much space unless you are attaching lots of files and images.
If you'd like to erase it: Open a class > Diary > Tools (top bar) > Delete diary annotations