diff --git a/doc/saio/swift/swift.conf b/doc/saio/swift/swift.conf
index f72a9ad5cf..e01a0ac881 100644
--- a/doc/saio/swift/swift.conf
+++ b/doc/saio/swift/swift.conf
@@ -1,5 +1,6 @@
 [swift-hash]
 # random unique strings that can never change (DO NOT LOSE)
+# Use only printable chars (python -c "import string; print(string.printable)")
 swift_hash_path_prefix = changeme
 swift_hash_path_suffix = changeme
 
diff --git a/doc/source/overview_policies.rst b/doc/source/overview_policies.rst
index 9ae2dcb468..5df03733d6 100755
--- a/doc/source/overview_policies.rst
+++ b/doc/source/overview_policies.rst
@@ -286,6 +286,7 @@ example configuration.::
 
         [swift-hash]
         # random unique strings that can never change (DO NOT LOSE)
+        # Use only printable chars (python -c "import string; print(string.printable)")
         swift_hash_path_prefix = changeme
         swift_hash_path_suffix = changeme
 
diff --git a/etc/swift.conf-sample b/etc/swift.conf-sample
index 839dea7cf1..86810caf90 100644
--- a/etc/swift.conf-sample
+++ b/etc/swift.conf-sample
@@ -4,6 +4,7 @@
 # the hashing algorithm when determining data placement in the cluster.
 # These values should remain secret and MUST NOT change
 # once a cluster has been deployed.
+# Use only printable chars (python -c "import string; print(string.printable)")
 
 swift_hash_path_suffix = changeme
 swift_hash_path_prefix = changeme