How to cleanup and manage overlay2 docker?

Description
Hi, I have a running docker container and my free disk space is infinitely decreases everyday. I have done as below :

Output of docker system df:

TYPE                TOTAL               ACTIVE              SIZE                RECLAIMABLE
Images              1                   1                   2.072GB             0B (0%)
Containers          1                   1                   12.66GB             0B (0%)
Local Volumes       0                   0                   0B                  0B
Build Cache         0                   0                   0B                  0B

Output of du --max-depth=1 -hc /var/lib/docker/overlay2/:

4.0K    /var/lib/docker/overlay2/l
205M    /var/lib/docker/overlay2/693a1e847468523f0d3cd2c90b190b8a23315d4e2581b7ea22785584415f3a9b
281M    /var/lib/docker/overlay2/64a9656875d0cf9c420d8dc58757e4f3fc6a7b8b66386c6bffeb2828af76fa1e
148M    /var/lib/docker/overlay2/f4612f13964de2437a9ebf264d895a0891aa7b4a232f5d20f16131f6eada18c6
85M     /var/lib/docker/overlay2/70b99605aa78817cac753c01cf4132b9698bece265a01751d4da1341d1f13be7
196K    /var/lib/docker/overlay2/9bd95ced09a685efd19bdee9efd0a97786ea8dcddeb2982928d3c27db773de59
418M    /var/lib/docker/overlay2/970856795dfd597524d694830c85246dd1f5cbc88de7364abe4eaba7ea27bd9e
16K     /var/lib/docker/overlay2/5490f4a0bdb240773b432c5bb593ee7cb195d3afc1a0e566a34ced4056ed98c4
419M    /var/lib/docker/overlay2/b600a8a8691217a3ce7a1cfa9b6b2784e67ee4f5b8b91e2840657d7f00b0cff9
452M    /var/lib/docker/overlay2/89aacbad54ddf4dc1b8e0accbadb9e85a600ff41c1e1cb13ff6b3c470f78b18e
8.0K    /var/lib/docker/overlay2/2ee426d956d3f9b4e9729c1e7df27ba3c29e533e2080a0fef71c508ae44e884d-init
16G     /var/lib/docker/overlay2/2ee426d956d3f9b4e9729c1e7df27ba3c29e533e2080a0fef71c508ae44e884d
18G     /var/lib/docker/overlay2/
18G     total

Output of docker system prune --all:

WARNING! This will remove:
  - all stopped containers
  - all networks not used by at least one container
  - all images without at least one container associated to them
  - all build cache

Are you sure you want to continue? [y/N] y
Total reclaimed space: 0B

Output of du -shc /var/lib/docker/overlay2/:

18G     /var/lib/docker/overlay2/
18G     total

How to cleanup and manage overlay2 docker ?

Source: Docker Questions