Email-list cleanup should remove confirmed import artifacts without inventing addresses or merging different records. Preserve the supplied address and keep uncertain entries visible.
Separate raw and cleaned fields
Copy the source into a retained raw column. Use a helper column for a reviewed whitespace cleanup, checking ordinary spaces and any confirmed nonbreaking characters separately.
Do not automatically change the local part before the @ sign or remove internal punctuation to make an address look familiar. A source-system rule is needed before treating character differences as equivalent identities.
Distinguish shape from deliverability
A pattern check can flag obvious problems such as a missing @ sign, but it does not prove that the mailbox exists, accepts mail, or belongs to the intended person. A visually plausible address can still contain a wrong domain.
Keep missing values missing and flag suspicious records for the appropriate owner. Do not guess a company domain, repair a typo by assumption, or fill blank addresses from an unrelated contact with a similar name.
Review duplicates and permitted use
Compare original and cleaned addresses, then inspect any collisions created by normalization. Repeated addresses may represent several source records rather than permission to collapse their histories.
Use a separate, explicit process for subscription status and consent. Cleanup does not authorize messaging or reinstate an opted-out recipient. Avoid exposing the list through public sharing or third-party validation tools without authorization. For recurring feeds, document exactly which transformations are accepted and retain an exception report so the next import does not silently turn uncertain contact data into apparently verified addresses.
References
Reviewed against the linked official product guidance on November 3, 2026. Features, limits, screen labels, and access can vary by account, platform, region, and organization policy.