Manage /snap folder
Ubuntu server continuously generates /snap files in the server that consume your server space. If you do not have any use of /snap you can purge that with below command.
$ sudo apt autoremove --purge snapd
After using the above command you can verify your file system with du command. du command require lots of options to display better result. so i would suggest to use ncdu package that can be install by below command.
$ sudo apt-get install ncdu
Once you install you can see all directory space in better way using ncdu command.
Below is the screenshot of above command.