code: public void cleanUp(RESTRequest request, int clientID) {
          ClientNotificationArea inbox = inboxes.get(clientID);
          //If somehow the inbox timed out before we came here, then just exit, because the end result is the same.
          if (inbox != null) {
              inbox.cleanUp(request);
              inboxes.remove(clientID);
          }
      }
docs: Cleanup specified clientID