diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index 5c14de35776..b561a6f73ad 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -1624,8 +1624,7 @@ def __del__(self):
         # sys.stdout.encoding is the OEM code page and these code pages are
         # implemented in Python
         rc, out, err = assert_python_ok("-c", code,
-                                        PYTHONIOENCODING="ascii",
-                                        __cleanenv=True)
+                                        PYTHONIOENCODING="ascii")
         self.assertEqual(["before", "after"], out.decode().splitlines())