[MEMO]Remove apt generated btrfs snapshots
By QQCif
In short
sudo btrfs subvolume list /
sudo apt-btrfs-snapshot delete @apt…
http://askubuntu.com/questions/464074/ubuntu-thinks-btrfs-disk-is-full-but-its-not
http://askubuntu.com/questions/441375/cant-delete-a-btrfs-snapshot
https://sites.google.com/site/easylinuxtipsproject/clean
https://help.ubuntu.com/community/Lubuntu/Documentation/RemoveOldKernels