the box that runs my mailsever just reported disk > 80% full , so looking to tidy up. I note:

sudo du -d2 -k -x /home/graeme/mail | sort -n ... ... 66788 /home/graeme/mail/.imap/spam 198328 /home/graeme/mail/.imap 1564680 /home/graeme/mail/2023 4009336 /home/graeme/mail

Now in .imap I have directories dating back to 2013 .... the corresponding mail folders have long since moved to backup. What would be the effect of deleting EVERYTHING in .imap.... will it just get recreated as needed? or do I need to take care and only remove stuff I know is no longer used?