We tried to create a mailing list with some of our existing contacts, and ended up cloning / duplicating those contacts.

When searching a name, 2 versions come up. If one is edited, the other one remains unedited, so they don't recognise one another as the same.

The risk here is that we may lose or duplicate information, so we need to either mass-merge or mass-remove the cloned contact. I am able to merge individual contacts, but this isn't plausible for hundreds of contacts.

How do we do this?

Thanks for your efforts,

Max