How to remove people and tags that are no longer associated with any photo?

I have been going back and forth between Lightroom Classic and Lightroom CC. I have migrated my entire library between the two and I use the people view feature in CC. Each time I go back to CC, I need to rename every person. However, in the search bar, the old tag does not go away. Now I have mutiple people tag with the exact same name but only one of them are connected to the actual pictures. If I click on an old tag, I get nothing. Is there any way for me to clear all the old people/tags and start fresh?