Clearing out the ~/mail directory

One of our cPanel users was previously using IMAP and switched over to pop3 and downloaded all of his emails (he did not have any folders).

Now his email account and the others all show in cPanel that they aren't taking up any space, expect for the time when they haven't checked their email yet.

However, in his ~/mail directory, there is a ./new directory. This directory is still taking up 2.1G.

Is it safe to clear this directory out, or what is the safe way to clear that out?

Finally, what are some options for people to archive their IMAP folders? Is there a way I can set a time limit on the server for deleted items and the spam assassin spam folder?

Thank you, as always.

 

For a different account, we just deleted an email account that had over 1g of data. Yet the total disk usage is not down after clearing that email account.