diff --git a/misc/migration_tools/remove_unused_authorities.pl b/misc/migration_tools/remove_unused_authorities.pl
index 5171538e83..28c651ff6f 100755
--- a/misc/migration_tools/remove_unused_authorities.pl
+++ b/misc/migration_tools/remove_unused_authorities.pl
@@ -84,10 +84,19 @@ print "$counter authorities parsed, $totdeleted deleted and $totundeleted unchan
 
 sub print_usage {
     print <<_USAGE_;
-$0: Removes unused authorities.
+$0: Remove unused authority records
+
+This script removes authority records that do not have any biblio
+records attached to them.
+
+If the --aut option is supplied, only authority records of that
+particular type will be checked for usage.  --aut can be repeated.
+
+If --aut is not supplied, all authority records will be checked.
+
+Use --test to perform a test run.  This script does not ask the
+operator to confirm the deletion of each authority record.
 
-This script will parse all authoritiestypes (or only those given as parameter), and remove authorities without any biblio attached.
-warning : there is no individual confirmation !
 parameters
     --aut|authtypecode TYPE       the list of authtypes to check
     --test or -t                  test mode, don't delete really, just count