Sugessions to manage the fileserver- File server space keeps growing.

Hi

We have our file server on windows 2012 and the share keeps growing and I noticed that these are departmental folders and files that are left and may not be required any more.
Its is the departmental responsibility take initiatives to go through and tidy up as what is needed and what is not required and needs deleted.

We have a media server  and users have been instructed to save media related files to the Media server. Instead many still the staff keep copying media related files to departmental shares and home drives, that keep the file server taking the space.

Not sure how you manage the growth of the space on the file servers. Do you send email periodically to reminding the staff to delete unnecessary files.

Any suggestions to manage this will be great.