What is email list cleaning?

Email list cleaning means checking every address on a list and removing the ones that will not receive mail: addresses that do not exist, dead domains, disposable inboxes and typos. You send only to addresses that can receive mail, so fewer messages bounce and mailbox providers see a sender who keeps their list in order.

Is list cleaning the same as email verification?

Verification is the check on each address. Cleaning is what you do with the whole list once you have the results: which addresses to remove, which to keep, and which to send to separately. BounceCheck runs the same engine as its bulk email verification, and this page explains how to act on each result.

Should I delete addresses that come back unknown?

Not all at once. Unknown means the receiving server would not give an answer, not that the mailbox is dead. In our data 46.2% of Yahoo and AOL addresses came back unknown, against under 0.5% for Google, Microsoft and iCloud. Send to unknown addresses in a separate, smaller batch and remove the ones that bounce.

Does BounceCheck email the people on my list?

No. Each address is checked against the receiving mail server without sending a message, so nobody on your list is contacted or notified.

Will cleaning change the list inside my email platform?

No. You get a results file. You then import the clean list, or add the invalid addresses to your platform's suppression list. Suppressing is safer than deleting, because a deleted contact can be re-imported by mistake later.

How often should I clean my email list?

Clean before you send to a list you have not mailed in a while, after you import contacts from another system or an event, and whenever your bounce rate starts to rise. Lists you mail every week with confirmed opt-in need it less often.

What file formats can I upload?

CSV, XLSX and TXT. Duplicates are removed before credits are used, so you pay only for unique addresses.

What happens to my file?

Your file and its results stay in your account so you can download them again, and are deleted when you delete your account. We never sell or share your list, and we never send mail to the addresses on it.

§ 01 / EMAIL LIST CLEANING

Email List Cleaning Service

Upload your list and get back a file that tells you which addresses to keep, which to remove, and which need a decision. Nobody on the list is emailed.

Clean my list What gets removed ↓

✓ 50 free checks a month✓ CSV / XLSX / TXT✓ Duplicates removed first✓ No emails sent

373 lists checked by BounceCheck users

34.5%

of addresses were invalid on the median list

Half of all lists18.0% to 60.6% invalid

1 in 10 lists80% or more invalid

Yahoo & AOL addresses46.2% unknown

How we measured this (data pulled 2026-11-04)

§ 02 / WHAT GETS REMOVED

Not every bad address should be deleted

A clean list is not just a shorter list. Some addresses must go, some only need to be sent to more carefully, and deleting the wrong group loses real subscribers. Every address in your results file carries one of these labels.

Invalid

The mailbox or the domain does not exist, or the address is malformed.

What to doRemove, and add to your suppression list.

Disposable

A throwaway inbox from a temp-mail service. It may accept mail today and be gone tomorrow.

What to doRemove from marketing lists.

Unknown

The receiving server refused the check or dropped the connection. Common with Yahoo and AOL.

What to doKeep, but send in a separate small batch and drop what bounces.

Catch-all

The domain accepts every address, so no verifier can confirm the mailbox.

What to doSegment and send with care. Watch the bounces on this group.

Role-based

Addresses like info@ or support@. Often real, but read by several people.

What to doKeep only if that address opted in. The risk is complaints, not bounces.

Duplicates

The same address appearing more than once in your file.

What to doMerged automatically before any credits are used.

In our data, catch-all domains were 8.6% of the domains checked and sit mostly on company domains rather than free providers. Role-based addresses were less likely to be invalid than personal ones (23.5% against 33.9%), which is why we mark them for a consent check instead of removing them. Read the details in what 597,834 verified addresses show, or what each result means in our guide to catch-all email.

§ 03 / HOW IT WORKS

From your email platform and back again

Export your list

Export contacts from Mailchimp, Klaviyo, HubSpot or your CRM as CSV or XLSX. Keep the email column; other columns come back untouched.

Upload to BounceCheck

Duplicates are merged first. Each address is then checked for syntax, domain and mail server, and probed at the mailbox without sending a message.

Suppress, segment, re-import

Download the results. Add invalid and disposable addresses to your suppression list, put unknown and catch-all in their own segment, and send to the rest.

Prefer to do it by hand first? Follow our 6-step list clean-up guide. Sending a big seasonal campaign? Use the 3-week Black Friday plan.

§ 04 / PRICING

Pay for unique addresses, not for duplicates

One credit checks one unique address. Need more than your plan for a single big clean? Add-on credit packs never expire.

Free

50 checks a month

No credit card

Starter

$9.99/month

5,000 checks a month

$7.99/month billed yearly

Pro

$29.99/month

20,000 checks a month

$23.99/month billed yearly

See full pricing and add-on packs

§ 05 / FAQ

Email list cleaning FAQ

Explore more

§ 06 / GET STARTED

Find out how much of your list can actually receive mail.

50 free checks every month. No credit card required.

Clean my list