Among your switches you have an "Revision Requests" option for comments. If someone has posted something which you don't think belongs on the site, but which you believe they could fix to make acceptable, you can request a revision. The option appears on the "Edit Comment" page when the switch is enabled, and it'll bring you to a prompt asking you to describe exactly what the person should fix. The post will become invisible and the member will be notified via private messaging or email. If they edit the post, it'll then show as pending validation where you can approve or reject the new version.