public void cleanDatabase() {
//Iterate through all forums, threads to delete unwanted messages.
Iterator forums = forums();
while (forums.hasNext()) {
Forum forum = (Forum) forums.next();
Iterator threads = forum.threads();
while (threads.hasNext()) {
try {
ForumThread thread = (ForumThread) threads.next();
Iterator messages = thread.messages();
while (messages.hasNext()) {