To delete your Grok chat history on grok.com/app and X, go to your chat...

https://stateofseo.com/how-do-i-handle-a-stubborn-grok-file-that-wont-delete/

To delete your Grok chat history on grok.com/app and X, go to your chat settings and choose clear history. Remember this moves items to Recently Deleted, where they stay for 30 days before final removal