From the comments there, it sounds like the real API might limit you to deleting messages created by your own app. Somebody also posted a Javascript solution where you double-click the 'delete' button to delete all older posts, but I'm not sure if it will work since the version information says "obsolete" in it.
From the comments there, it sounds like the real API might limit you to deleting messages created by your own app. Somebody also posted a Javascript solution where you double-click the 'delete' button to delete all older posts, but I'm not sure if it will work since the version information says "obsolete" in it.