vBulletin bulk delete members
How to bulk delete SPAM accounts including posts they made on an vbuleltin forum? Bulk delete all SPAMmer accounts matching criteria?
AdminCP > Users > Move/Prune Users
Second idea (one by one deleting):
AdminCP > Users > Search for Users
spammer accounts may have common signs, once youa re on user list, click "Go" button next to username to edit it, then from "Quick User Links" dropdown menu select "Delete user" option. and then there is this text line: "If you want to prune all the user's messages first, please click here.". Once member have 0 posts, one can use "AdminCP > Users > Move/Prune Users" to bulk delete all accounts with zero posts.
If you deleted bad Threads manually from database (example via PHPMyAdmin), it may (im not sure) leave some Treads related data in other database tables. So one may try removing orphaned posts from that deleted threads by vbulletin maintenance tools (not sure if it would be fully effective):
AdminCP / maintenance / General update tools
on the bottom is:
> Remove Orphan Posts <
This function removes all posts that belong to threads that no longer exist.