You can use the command docker image prune to remove unused images:

$ docker image prune --help

Usage: docker image prune [OPTIONS]

Remove unused images

Options:
  -a, --all             Remove all unused images, not just dangling ones
      --filter filter   Provide filter values (e.g. 'until=<timestamp>')
  -f, --force           Do not prompt for confirmation

First, let's list existing images:

$ docker image ls

REPOSITORY                    TAG             IMAGE ID            CREATED             SIZE
zookeeper-multi-stage         3.6.1           673b3d044115        9 minutes ago       40.8MB
<none>                        <none>          95c0f0969c15        9 minutes ago       55.1MB
alpine                        latest          a24bb4013296        2 months ago        5.57MB

By default, only regular and dangling images are shown.
A dangling image is one that is not tagged and is not referenced by any container.

Use the option -a (--all) to list all images:

$ docker image ls -a

REPOSITORY                    TAG             IMAGE ID            CREATED             SIZE
zookeeper-multi-stage         3.6.1           673b3d044115        12 minutes ago      40.8MB
<none>                        <none>          95c0f0969c15        12 minutes ago      55.1MB
<none>                        <none>          95e1e698e91f        12 minutes ago      19.8MB
<none>                        <none>          54616be057e7        12 minutes ago      7.4MB
alpine                        latest          a24bb4013296        2 months ago        5.57MB

Remove dangling images:

$ docker image prune

WARNING! This will remove all dangling images.

Are you sure you want to continue? [y/N] y
Deleted Images:
deleted: sha256:95c0f0969c156a7bba1c94636a04e903ff01bba68b2b6938d69e9dbd3e0df71e
deleted: sha256:2ffccaa21550779cbd06bb923d287fcb9956944d9580553d7b0351f2449f62d1
deleted: sha256:95e1e698e91fc643b11bd4f1b725966348e7125aaac4e6fc2a00dd615b2f23e3
deleted: sha256:c6d4e880f3e27836c4b13e4125933938d185eebad9580a0bf5e0dc368cf225f0
deleted: sha256:54616be057e7549cd225a67e06b515eeafbe85d6e9b69541cf60b43d61c1ddd1
deleted: sha256:8caf8b6e850679bfe3d3d4c1369d399e0a17c8c085f312eabf1454d9107a111a

Total reclaimed space: 49.51M

Check that dangling images were deleted:

$ docker image ls -a

REPOSITORY                    TAG             IMAGE ID            CREATED             SIZE
zookeeper-multi-stage         3.6.1           673b3d044115        12 minutes ago      40.8MB
alpine                        latest          a24bb4013296        2 months ago        5.57MB

It's also possible to use this command to remove dangling images:

$ docker image rm $(docker image ls -q -f "dangling=true")

You can use the command docker buildx prune to remove build cache:

$ docker buildx prune --help

Remove build cache

Usage:  docker buildx prune

Remove build cache

Options:
  -a, --all                    Include internal/frontend images
      --builder string         Override the configured builder instance
  -D, --debug                  Enable debug logging
      --filter filter          Provide filter values (e.g., "until=24h")
  -f, --force                  Do not prompt for confirmation
      --max-used-space bytes   Maximum amount of disk space allowed to keep for cache
      --min-free-space bytes   Target amount of free disk space after pruning
      --reserved-space bytes   Amount of disk space always allowed to keep for cache
      --verbose                Provide a more verbose output

Experimental commands and flags are hidden. Set BUILDX_EXPERIMENTAL=1 to show them.

Let's create a simple Dockerfile:

$ vi Dockerfile

FROM ubuntu:latest

Let's build the Dockerfile:

$ docker build -t ubuntu-test:latest .

Clear build cache:

$ docker buildx prune --all --verbose

WARNING! This will remove all build cache. Are you sure you want to continue? [y/N] y
ID: 52cwy2cp9vd6od07xk2ux0xgk
Created at: 2024-06-15 15:14:54.395180592 +0000 UTC
Mutable: false
Reclaimable: true
Shared: false
Size: 29.72MB
Usage count: 1
Last used: 2 minutes ago

Total: 29.72MB

You can use the command docker container prune to remove all stopped containers:

$ docker container prune --help

Usage: docker container prune [OPTIONS]

Remove all stopped containers

Options:
      --filter filter   Provide filter values (e.g. 'until=<timestamp>')
  -f, --force           Do not prompt for confirmation

Let's start a container:

$ docker container run ubuntu:latest

5447b485b834c8125a4b6fceb0aaf1be1f39fa36b8247320246ba9b792e52f39

Check the container:

$ docker container ls -a

CONTAINER ID    IMAGE           COMMAND         CREATED          STATUS                     NAMES
5447b485b834    ubuntu:latest   "/bin/bash"     6 seconds ago    Exited (0) 5 seconds ago   distracted_hoover

Note that the container was started and executed the command /bin/bash, but then exited because no process was running in the foreground or background.

Remove stopped containers:

$ docker container prune

WARNING! This will remove all stopped containers.

Are you sure you want to continue? [y/N] y
Deleted Containers:
5447b485b834c8125a4b6fceb0aaf1be1f39fa36b8247320246ba9b792e52f39

Total reclaimed space: 0B

It's also possible to use this command to remove all containers with the status exited:

$ docker container rm $(docker container ls -a -q --filter "status=exited")

You can use the command docker network prune to remove all unused networks (not attached to a running container):

$ docker network prune --help

Usage: docker network prune [OPTIONS]

Remove all unused networks

Options:
      --filter filter   Provide filter values (e.g. 'until=<timestamp>')
  -f, --force           Do not prompt for confirmation

Create a test network:

$ docker network create network1

1f1873ef27f8a4bedceef2dd3f9e687216d2f648b544ced4610bfcd55fb507ba

Remove unused networks:

$ docker network prune

WARNING! This will remove all custom networks not used by at least one container.

Are you sure you want to continue? [y/N] y
Deleted Networks:
network1

You can use the command docker volume prune to remove all unused local volumes (not attached to a running container):

$ docker volume prune --help

Usage:  docker volume prune [OPTIONS]

Remove unused local volumes

Options:
  -a, --all             Remove all unused volumes, not just anonymous ones
      --filter filter   Provide filter values (e.g. "label=<label>")
  -f, --force           Do not prompt for confirmation

Create a test volume:

$ docker volume create volume1

volume1

Let's use the created volume:

$ docker container run --rm --volume volume1:/cvdata ubuntu:latest /bin/bash -c "echo 'hello docker volumes' > /cvdata/file1.txt"

d58173f7f8c81b429d0a0e015f864a4797c9ffb7f1c22bec2e3a1e0932f776dc

Let's check the data in the volume:

$ docker container run --rm --volume volume1:/cvdata ubuntu:latest /bin/bash -c "cat /cvdata/file1.txt"

hello docker volumes

Let's remove the unused volumes:

$ docker volume prune --all

WARNING! This will remove all local volumes not used by at least one container.
Are you sure you want to continue? [y/N] y
Deleted Volumes:
volume1

Total reclaimed space: 21B

You could also remove specific volumes using the command docker volume rm:

$ docker volume rm --help

Usage:  docker volume rm [OPTIONS] VOLUME [VOLUME...]

Remove one or more volumes. You cannot remove a volume that is in use by a container.

Aliases:
  docker volume rm, docker volume remove

Options:
  -f, --force   Force the removal of one or more volumes

You can also use the command docker system prune to remove all unused objects. This will remove unused images, build cahce, stopped containers, and unused networks:

$ docker system prune --help

Usage:  docker system prune [OPTIONS]

Remove unused data

Options:
  -a, --all             Remove all unused images not just dangling ones
      --filter filter   Provide filter values (e.g. "label=<key>=<value>")
  -f, --force           Do not prompt for confirmation
      --volumes         Prune anonymous volumes

Remove unused objects (note the option --volumes to also remove unused local volumes):

$ docker system prune --volumes

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 dangling images
  - all dangling build cache

Are you sure you want to continue? [y/N] y
Deleted Containers:
437d593134a15ce50fd9427713cdeabfa40eb94bf2577684a2317bf213afb35c

Deleted Networks:
network1

Deleted Volumes:
volume1

Deleted Images:
deleted: sha256:95c0f0969c156a7bba1c94636a04e903ff01bba68b2b6938d69e9dbd3e0df71e
deleted: sha256:2ffccaa21550779cbd06bb923d287fcb9956944d9580553d7b0351f2449f62d1
deleted: sha256:95e1e698e91fc643b11bd4f1b725966348e7125aaac4e6fc2a00dd615b2f23e3
deleted: sha256:c6d4e880f3e27836c4b13e4125933938d185eebad9580a0bf5e0dc368cf225f0
deleted: sha256:54616be057e7549cd225a67e06b515eeafbe85d6e9b69541cf60b43d61c1ddd1
deleted: sha256:8caf8b6e850679bfe3d3d4c1369d399e0a17c8c085f312eabf1454d9107a111a

Total reclaimed space: 49.51M