I too am wondering about this issue. Each year, I have hundreds of documents uploaded to my moodle. When the students leave, I don't want their uploads anymore. But of course, they must be taking up space on the server and/or the database is getting bloated.
I have rights to delete things in the repository directly on the server. But seeing as moodle isn't transparent about where things are kept, nor does it make human readable names for uploaded things, how am I to actually delete these uploaded documents?
Plus, if I delete them from the repository manually, what will that do to the links in the database that point to these files if they become non-existent?
Can someone knowledgeable about the inner workings of Moodle comment on this issue please?