Contacts Duster Pro is a mediocre interfaced but useful app. Fortunately it includes a nice online FAQ/manual to help direct you in using ContactsDusterPro . With one click, or when opened, it automatically scans your sources and contacts for duplicates and presents them all to you. ContactsDusterPro even has the ability to graph the results. One can choose from which source to prefer when the contacts are merged and/or deleted. A handy backup is included to protect your contacts database just in case there are problems. From there, you can choose what you want to do with your contacts individually (includes a nice preview feature), or just click a button and let the process be fully automated by the duster. Export selected or all contacts via vcf to any email. My only recommendation is to make a setting where you can set the contact preference to Local, Cloud, etc. for all contacts, rather than having to do so individually. Straight forward and useful, although graphically plain and slightly buggy, ContactsDusterPro is recommended if you have a large set of contacts.