To delete your Grok chat history on grok.com/app and X, open your chat settings...

https://sierra-wiki.win/index.php/How_Do_I_Stop_Grok_from_Using_My_Chats_for_Training_on_Grok.com%3F

To delete your Grok chat history on grok.com/app and X, open your chat settings and choose 'Delete Conversation.' Remember, deleting chat doesn’t remove files or images from Imagine—you’ll need to delete those separately