Every experienced WordPress user knows the importance of performing maintenance on their database regularly. You can always use phpMyAdmin to do it manually but there are plenty of plugins that save you time doing so. Smart Cleanup Tools for WordPress comes with a set of features to help you properly clean up your database.
Thanks to these plugins, you can remove trashed, spammed, orphaned posts and comments. You can also remove any database overhead and transient records. You can use it to remove unapproved comments, draft posts, and attachments that are not attached to any posts. For each of these tools, you are shown records found, estimated size or overhead that can be removed.
Smart Cleanup Tools lets you schedule clean up jobs automatically. SMARTPlugins is the developer behind it.