I do not know if you can do this, but I can not. I clear chat log in settings, then if you log out of game and come back in, the chat log is back. This is not good if your running the same module for different players, as they can see your creature rolls from before and know what to expect. Is there a way to permanently delete that chat log or if not can you add this. This would save roll 20 more storage space too.