diff --git a/README.md b/README.md
index b19e4f3..d328d20 100644
--- a/README.md
+++ b/README.md
@@ -350,6 +350,11 @@ It should not be neccessary to reload this configuration manually, as it is auto
 It is also possible to manually add a URI prefix to an instance.
 For this purpose, add a file named `prefixes` to the base directory of the instance, with one prefix per line.
 
+Furthermore, you can also exclude a specific instance from URL prefix resolving.
+This should be the case for cloned or backup instances.
+For this purpose, add a file named `prefixes.skip` to the base directory of the instance.
+This will casuse the instance to be skipped entirely.
+
 ## License
 
 This project and associated files in this repository are licensed as follows:
diff --git a/distillery/lib/30_slug.sh b/distillery/lib/30_slug.sh
index 8c6341d..1679365 100644
--- a/distillery/lib/30_slug.sh
+++ b/distillery/lib/30_slug.sh
@@ -84,6 +84,14 @@ function compute_instance_prefixfile() {
 }
 INSTANCE_PREFIX_FILE="$(compute_instance_prefixfile "$INSTANCE_BASE_DIR" )"
 
+# compute the prefix file
+function compute_instance_noprefixfile() {
+    INSTANCE_BASE_DIR="$1"
+    INSTANCE_PREFIX_FILE="$INSTANCE_BASE_DIR/prefixes.skip"
+    echo "$INSTANCE_PREFIX_FILE"
+}
+INSTANCE_NOPREFIX_FILE="$(compute_instance_noprefixfile "$INSTANCE_BASE_DIR" )"
+
 if [ -n "$CERTBOT_EMAIL" ]; then
     LETSENCRYPT_HOST="$INSTANCE_DOMAIN"
     LETSENCRYPT_EMAIL="$CERTBOT_EMAIL"
diff --git a/distillery/update_prefix_config.sh b/distillery/update_prefix_config.sh
index f73da21..76f46f9 100644
--- a/distillery/update_prefix_config.sh
+++ b/distillery/update_prefix_config.sh
@@ -16,18 +16,24 @@ date | tee -a "$DEPLOY_PREFIX_CONFIG"
 # update all the instances
 for slug in $(sql_bookkeep_list); do
     INSTANCE_DOMAIN="$(compute_instance_url "$slug")"
-    echo "$INSTANCE_DOMAIN:" | tee -a "$DEPLOY_PREFIX_CONFIG"
     
     read -r INSTANCE_BASE_DIR MYSQL_DATABASE MYSQL_USER GRAPHDB_REPO GRAPHDB_USER GRAPHDB_PASSWORD <<< "$(sql_bookkeep_load "${slug}" "filesystem_base,sql_database,sql_user,graphdb_repository,graphdb_user,graphdb_password" | tail -n +2)"
 
+    INSTANCE_NOPREFIX_FILE="$(compute_instance_noprefixfile "$INSTANCE_BASE_DIR" )"
+    INSTANCE_PREFIX_FILE="$(compute_instance_prefixfile "$INSTANCE_BASE_DIR" )"
+    if [ -f "$INSTANCE_NOPREFIX_FILE" ]; then
+        continue
+    fi
+
     pushd "$INSTANCE_BASE_DIR" > /dev/null
 
-    INSTANCE_PREFIX_FILE="$(compute_instance_prefixfile "$INSTANCE_BASE_DIR" )"
+    echo "$INSTANCE_DOMAIN:" | tee -a "$DEPLOY_PREFIX_CONFIG"
+    docker-compose exec barrel /user_shell.sh -c "drush php:script /wisskiutils/list_uri_prefixes.php" | tee -a "$DEPLOY_PREFIX_CONFIG"
+
     if [ -f "$INSTANCE_PREFIX_FILE" ]; then
         cat "$INSTANCE_PREFIX_FILE" | tee -a "$DEPLOY_PREFIX_CONFIG"
     fi
     
-    docker-compose exec barrel /user_shell.sh -c "drush php:script /wisskiutils/list_uri_prefixes.php" | tee -a "$DEPLOY_PREFIX_CONFIG"
     popd > /dev/null
 done