A cold-email agency cleans a catch-all-heavy prospect list

The situation

Picture a small cold-email agency running outbound campaigns for B2B clients. Every campaign starts the same way: a prospect list assembled from scraping tools, data providers, and client CRM exports — thousands of contacts, in mixed condition, on a deadline. The agency's sending domains are its livelihood: they took months to warm up, and a single bad send can throttle deliverability for every client on the calendar.

The agency already verifies every list before sending. The problem isn't the obviously-bad addresses — any verifier catches those. The problem is what comes back in the middle.

The pain: catch-alls are an unknown most verifiers won't touch

Run a B2B list through a standard verifier and a large slice comes back labeled "catch-all", "accept-all", or "risky" — roughly 40-60% of B2B email addresses live on catch-all domains. A catch-all mail server accepts mail to any address, even ones that don't exist, so a standard check can't tell which of those contacts are real. Most tools simply punt: they flag the segment and tell you to skip it.

For a cold-email agency, both ways out of that label are expensive. Delete the risky segment and you throw away a huge share of the prospects the client paid for. Send to it blind and unverified catch-all addresses bounce at 27x the rate of standard emails — spam traps hide on catch-all domains, ESPs throttle accounts whose bounce rates climb past 2%, and the sending domain takes the damage.

The agency doesn't need another tool to tell it which addresses are catch-all. It needs one that can answer the actual question: which of these catch-all addresses are real? That's the case for a dedicated catch-all verifier.

The workflow, step by step

1. 1

   Clean the raw CSV first

   Prospect exports arrive messy: duplicate rows from overlapping sources, inconsistent columns, contacts that don't fit the campaign. Before spending a single credit, the agency runs the file through Enrichley's free CSV Cleaner to dedupe, merge, split, and filter it down to the rows worth verifying.

2. 2

   Bulk-verify the whole list

   The cleaned CSV goes into Enrichley for bulk verification. Every address is verified in real time at 1 credit per email — the same credits that power the rest of the platform — and each one comes back with a clear verdict instead of a shrug.

3. 3

   Let the catch-alls resolve instead of skipping them

   This is the step most verifiers can't do. Enrichley's catch-all verifier resolves each address on an accept-all domain to valid or invalid in real time, at 98% accuracy, without ever sending a test email to the recipient. Instead of deleting the "risky" segment, the agency typically recovers 20-30% more usable emails from the same list — the contacts its competitors discard. (The full mechanics are in How to Verify Catch-All Emails.)

4. 4

   Send only to confirmed-valid addresses

   The agency exports the verified results and builds the campaign from the "valid" segment only. Invalid addresses are dropped, and nothing goes out on a guess — the discipline that keeps bounce rates under the 2% line ESPs watch and protects the sending domains the agency spent months warming up.

5. 5

   Spam-check the copy before launch

   A clean list can still be sunk by risky copy. Before the sequence goes live, the copy gets a pass through the free Spam Checker, which scans for 500+ known trigger words so the message isn't flagged before it's ever read.

The outcome

The list that comes back is safe to send. Instead of a "risky" segment sitting in limbo, every catch-all address has a verdict — and the valid ones stay in the campaign rather than in the trash. The agency reaches prospects its competitors never contact, because those competitors' verifiers told them to skip the very same addresses.

Just as important is what doesn't happen: no blind sends into accept-all domains, no bounce spikes, no burned sending domains. The same verify-first discipline repeats for every campaign, because email data decays constantly — the full playbook is on our cold email use-case page.