Specification drafting
Scoped, matched, and written down.
Work is scoped against what the sources can actually support. Suppression is applied at the start, so the approved figure is the delivered figure. The handover includes what was removed, and why it was removed.
Syntax screening
Removing malformed and obviously generated addresses before anything is paid to check them.
Catch-all detection
Separating addresses that are confirmed from addresses on a domain that accepts anything.
Mailbox shape
Distinguishing an individual's address from a shared or departmental one before either is used.