Spam cleaner
From MoodleDocs
Location: Settings > Site administration > Reports > Spam cleaner
The Spam cleaner can be used to locate user accounts responsible for spam and other nasty stuff and help you delete them.
It allows you to search user profiles for particularly spammy keywords, then presents you with a result list which you can browse and then easily delete problem user profiles.
See also
- Reducing spam in Moodle
- Why porn spam has been appearing in Moodle sites for background information