diff --git a/backup/README.md b/backup/README.md
index f22548e..e46c21f 100644
--- a/backup/README.md
+++ b/backup/README.md
@@ -1,5 +1,13 @@
 # Generic Backup Host
 
+## Crontab
+
+Runs on the second of every month.
+
+```
+0 0 2 * * cd /home/USER/backups && bash prune.sh
+```
+
 ## Filenames
 
 Container volume backups are of the format:
diff --git a/backup/prune.sh b/backup/prune.sh
index 38c4bca..5bdff32 100644
--- a/backup/prune.sh
+++ b/backup/prune.sh
@@ -1,15 +1,14 @@
 #!/usr/bin/bash
 
-# Prunes container data folders monthly on backup host
-# - Regex has been tested and works
-# - Script is not yet tested
+# Prunes container data folders monthly on backup host.
+# Removes all items but the backup from the first day of the month.
+# Should run on the first day of every month - since it doesn't remove the backup
+# from that time, it doesn't matter what time it's run
 
-ARCHIVES=$(ls | grep -E "[0-9A-Za-z]+-data-\d{4}-\d{2}-([^0][0-9]|[0-9][^1])_.*")
-
-for archive in $ARCHIVES; do
-    if [ -d $archive ]; then
-        echo "Removing $archive"
-        rm -f $archive
+for item in *; do
+    if [[ "$item" =~ [0-9A-Za-z]+-data-[0-9]{4}-[0-9]{2}-([^0][0-9]|[0-9][^1])_.* ]]; then
+        echo "Removing $item"
+        rm -f $item
     fi
 done