Thread:Rappy/@comment-6009751-20180822194908/@comment-27345308-20180822213230

I'm not sure what you mean by "deleting" welcome messages, but unless you used AjaxThreadDelete to delete them the redlinks still exist, the pages are just hidden. You can either use the mentioned script to actually delete these pages or edit the threads to remove the redlinks.

Special:Nuke is for dealing with vandalism, not redlinks.