How to delete all posts and forums?

[romaine]

I restored a vB 4 on a different hosting to test and I want to delete all posts and forums there but keeping members but the problem is I want to have new posts or forums that like a clean forum does, i.e

forum id starts from 1
post id starts from 1

I am thinking about empty forums and posts table in Phpmyadmin but I don't know that's possible or not because I think vBulletin table has relationships together so If I delete them, maybe cause some conflicts on forum?

Please advise me. Thanks!