I had a comment entered on my dog agility blog that I subsequently deleted and of course my lastcommented plugin recorded the comment as the most recent comment. Since the plugin uses Storable to store the data I couldn't manually edit the file to remove the entry.
So I modified my lastcommented plugin to allow you to specify the, base zero, index of the entry on the URL and delete the entry. For example to delete the second entry in the list (index 1):
To keep mischief makers from deleting all your comments the plugin has a variable in its configuration section called lastcommentremove that you set to a non zero value to enable this feature. Since this is probably a relatively infrequent activity (if you have blacklisting or wbcaptcha comment spam protection enabled) I figured this was a sufficient mechanism.