Remove all content after removing user

[Managers United]

Hi, 

Question: How do I remove one person's posts after deleting his account? On the forum it now states 'Guest Nickname' after an account was banned and then removed.

How do I delete all the posts marked like this?

[opentype]

You need to delete the content before deleting the account. Once deleted, there is no user anymore. The posts are just guests posts. So you can’t easily access a specific user’s posts anymore from the ACP or the front end. 

[Managers United]

Okay. Thats crap, cause someone deleted the account already. Is there a way to delete al 'Guest' content?

[Managers United]

11 minutes ago, opentype said:

You need to delete the content before deleting the account. Once deleted, there is no user anymore. The posts are just guests posts. So you can’t easily access a specific user’s posts anymore from the ACP or the front end. 

Is see now that there is an option in Spam Prevention. But, that keeps getting a 504 time out... Could that be because it are over 10k posts? Should I keep on using it, meaning: does it work in the background despite the 504 gateway timeout?