diff --git a/t/run.t b/t/run.t
index 2fd4079..078d587 100644
--- a/t/run.t
+++ b/t/run.t
@@ -107,3 +107,8 @@ eval {
   }
 };
 ok(!$@, "modify some header fields ($@)");
+
+### clean temporary files
+unlink('t/3.out');
+unlink('t/4.out');
+unlink('t/5.out');