Peter, you can use GAMADV-XTD to clear or delete contacts from users. At a simple level, you can use (see below) to
clear a specific email address from users contacts. Clear will allow all the other data in the contact to remain. From what I understand,
delete will remove the contact completely.
gam ou_and_children_ns <enter your top level OU here> clear contacts emailmatchpattern <enter contact email address to remove here>
Note, the syntax ou_and_children_ns will perform the gam command on all the active users (not suspended) in the top level OU you specify and in all the OU's under it.
For example I used this to clear the old Senior Management email address from all the contacts in the users in our Staff OU and sub-OUs.
James