A while ago I was finding that ncdu / shows that docker is using a lot
of disk space. I showed how to remove volumes in Manage Docker Volume
Disk Size. But volumes are not the only thing that can claim disk
space.
A usual suspect are images that are not used anymore. You can get a list of images that are not tagged anymore via:
docker images -q --filter "dangling=true"
To delete them all, hit:
docker rmi $(docker images -q --filter "dangling=true")