Delete old builds of unfollowed project

I’m wondering how to delete old builds from an unfollowed project.

Essentially, I’d like to reset the build history to be empty.

Instead, if I refollow, I see all the old builds that I’m trying to discard.

Do I just need to wait a while for some kind of delete worker or expiry threshold to kick in and then add the project back to circleci?

You would need to contact CircleCi and request the project be deleted from the server.

https://circleci.com/docs/faq/#how-can-i-delete-my-project