How do I find where an email is being used?

I had cloned an email from 1 program into a different program and then renamed the email.  I played around with the email too much and it is completely unusable now, so I want to delete it.  (I know - archiving is a best practice, but this email truly needs to be deleted!)

However, when I attempt to delete the email, it says it is in use and cannot be deleted.  I have confirmed that the original program it was cloned from points to the original email (again, the cloned version has a new name) and it is also not being used in the new program that it was cloned to.  I have no idea where else it could be in use - any ideas for how to search to find where an email is being used?