Use this to delete everything:
docker system prune -a --volumes
Remove all unused containers, volumes, networks and images
WARNING! This will remove:
- all stopped containers
- all networks not used by at least one container
- all volumes not used by at least one container
- all images without at least one container associated to them
- all build cache
https://docs.docker.com/engine/reference/commandline/system_prune/#extended-description