List cleaning
How a list got dirty decides what cleaning it will achieve. A list you bought and a list you neglected fail in different ways.
These pages are written per situation rather than per feature. Each one starts with where the bad addresses came from, because that tells you what share of the problem a verifier can remove and what share it cannot touch.
Two of them carry a warning you won't enjoy. Verifying a purchased list removes the addresses that bounce and leaves the consent problem exactly where it was. A re-engagement send to a list that has sat for two years will surface spam traps no tool can see.
CRM data cleaning
A CRM address sits on a person, a company and a deal, so deleting a bad row destroys call notes and deal history. Flag the field invalid and keep the record.
Email list cleaning
List cleaning removes addresses that servers reject, dead domains and disposables. It cannot confirm a mailbox on a catch-all domain or tell if anyone reads.
Email list hygiene
List hygiene is what stops you needing to clean a list, and it is a set of habits at the point addresses arrive rather than an operation performed on a database.
Email scrubbing
Scrubbing is list cleaning against a send date. Scrub close to the send, mail your engaged segment first, and hold unresolved rows out of the first wave.
Inherited list cleanup
Nobody recorded how an inherited list was collected, so a clean verdict proves the mailbox works, not that anyone opted in. Find the suppression list first.
Purchased list cleanup
Cleaning a purchased list removes the dead rows and does nothing about consent or pristine spam traps. If you mail it at all, never use your main domain.
Re-engagement cleanup
A dormant list fails in a way cleaning cannot see: the addresses still accept mail, and the problem is that nobody has opened one in two years.
Sign-up typos
Most sign-up typos land on domains that do not exist, like gmial.com, and cleaning comes too late to win the customer back. Verify at the form instead.
Run a sample through it
100 free checks a month, no card, and the unknowns come back labeled.