We frequently try to match facebook event attendees to contacts in our database in order to send targeted emails to the person. By matching them to our database we know a lot more about the people (e.g. geolocation to include reference to an elected representative). The process in civi to do this is cumbersome. We take the list of people from facebook (names only) and assign an external ID, then import the list to civi. We assume that names are unique (a somewhat reasonable assumption for our database). Following this process we want to free up the contact's external ID field to allow the next import to run without having to manually de-dupe anyone who has an external ID previously set. How can we either:
Do this without external IDs
Reset the external ID to null
We are using wordpress 4.4.1 and civi 4.6.10