diff --git a/focker.py b/focker.py
index 5947ff1..239796f 100644
--- a/focker.py
+++ b/focker.py
@@ -4,7 +4,8 @@ import os
 # from weir import zfs, process
 from .image import command_image_build, \
     command_image_untag, \
-    command_image_list
+    command_image_list, \
+    command_image_prune
 import sys
 from .zfs import zfs_init
 from .jail import command_jail_run
@@ -28,6 +29,9 @@ def create_parser():
     parser.set_defaults(func=command_image_list)
     parser.add_argument('--full-sha256', '-f', action='store_true')
 
+    parser = subparsers.add_parser('prune')
+    parser.set_defaults(func=command_image_prune)
+
     subparsers = subparsers_top.add_parser('jail').add_subparsers()
     parser = subparsers.add_parser('run')
     parser.set_defaults(func=command_jail_run)
diff --git a/image.py b/image.py
index c0759fc..26bc53c 100644
--- a/image.py
+++ b/image.py
@@ -88,3 +88,23 @@ def command_image_list(args):
         a[2] if args.full_sha256 else a[2][:7],
         a[4].split('/')[-1].split('@')[0] ], lst))
     print(tabulate(lst, headers=['Tags', 'Size', 'SHA256', 'Base']))
+
+
+def command_image_prune(args):
+    again = True
+    while again:
+        again = False
+        lst = zfs_parse_output(['zfs', 'list', '-o', 'focker:sha256,focker:tags,origin,name', '-H'])
+        used = set()
+        for r in lst:
+            if r[2] == '-':
+                continue
+            used.add(r[2].split('@')[0])
+        for r in lst:
+            if r[0] == '-' or r[1] != '-':
+                continue
+            if r[3] not in used:
+                print('Removing:', r[3])
+                zfs_run(['zfs', 'destroy', '-f', r[3]])
+                again = True
+    # zfs_parse_output(['zfs'])