Bulk clear Name fields?

I migrated from phplist 2.x to 3.x (latest and greatest) and I have quite a bit of records with one or more question marks in the Name field because the name contained special characters and they could not be imported properly (Kindly point me in the direction of instructions how to avoid that in the future when importing lists (new customers from a different system)).

When I do a search for ? using the Name field I find 700 such records.

Can you recommend a way to clear the name field for just those 700 records ?
I can’t think of anything using phplist ?

Is there a way to export just those people, based on that search criterion ?
I could then for instance make a temporary list, import them to that list and send them an email with the link to edit their record ?

Or … feel free to recommend something.