A bad list is the fastest way to burn a domain: 10% dead addresses in one batch and providers block you for weeks. Cleaning is not a one-off before the campaign, it is hygiene that runs all the time.
This guide covers verification, catch-all addresses, removing bounces, the blocklist and unsubscribes. Colldly does all of it automatically, but you should know what happens and why.
Have addresses verified before sending
Verification runs automatically between finding a company and adding it to a campaign. Non-existent addresses are removed, risky ones flagged.
Decide about catch-all addresses
A catch-all domain accepts email to anything, so it cannot be verified whether the mailbox exists. With a healthy bounce rate contact them freely; with worsening deliverability leave them out.
Remove bounces straight away
A hard bounce means the address does not exist. The system removes it on its own, but when you import your own lists, go through them before the next wave.
Use the blocklist
Add clients, competitors and people who do not want to hear from you to the blocklist. The system skips them in all campaigns of that brand.
Respect unsubscribes immediately
An unsubscribe is processed automatically and the address goes to the suppression list. Never put it back into a campaign; it is not only rude but legally risky.
Don't stockpile
A list found a year ago is largely invalid today. Better to search smaller batches continuously than one huge batch for the future.
- Every address is verified before the first email
- Catch-all addresses are flagged and you send to them carefully
- Hard bounces are removed and never return
- Clients, partners and competitors are on the blocklist
- Unsubscribes are processed immediately and automatically
- You do not stockpile contacts you cannot reach within a month