Is there a way to Dedupe Leads and Contacts together?

Is there a way to Dedupe Leads and Contacts together?

I have a lead database that also has duplicates of about 5,000 of my contact records.  I'm challenged that the built-in  dedupe functionality will only work within EITHER Leads or Contacts but will not dedupe across the two types of records.  Can anyone suggest a workaround for this, other than merging all my leads in the contacts? Thank you for any suggestions.