When you sync your contacts, you don't really need to delete them from the app . . .you can label them or sort them.
Once you're in the prospector section, you click on Sort Contacts or All Contacts:
You will then see the full list of contacts; with this menu on the top:
If you click on a contact, you'll be able to sort them; if it's someone that you don't need, mark them as Unworkable:
