To delete your Grok chat history, go to grok.com/app and clear conversations...

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, go to grok.com/app and clear conversations directly there. On X, remove chats by selecting and deleting messages from the thread