delete mails in promotions, social, forums which are older than 1 month

gistfile1.txt

function deleteMail() {
  var filter = "{category:promotions category:social category:forums} in:spam -in:starred -in:important older_than:5d"
  var threads = GmailApp.search(filter, 0, 100);
  Logger.log("Deleting " + threads.length);

  for (var i = 0; i < threads.length; i++) {
    Logger.log("Deleting .. " + threads[i].getFirstMessageSubject());
    threads[i].moveToTrash();
  }
}