Using a WhiteListed server to send your campaigns, you need to know a few things first.
Its very important to understand the difference between WHY you want to use a whitelisted server vs your own mailing server.
This is their lifeline and if their IP’s get damaged because your list is dirty, can’t inbox, bounce or get too many complaints then they will suspend or cancel your account all together.
So you have to understand when you simply upload a list to say MailChimp to send out your campaign, they scan your entire list as its being uploaded to your account. They have the most up to date suppression lists of bad data and compare what your uploading to their suppression lists. If you hit a certain threshold of bad data, being bad domains, role accounts, spam traps, honey pots, litigators etc, they simply stop your upload and send you a warning.
At this point its up to you to scrub and verify your data thoroughly, its not their job to that. The whitelisted server expects that every customer is legit and has a double opt-in list and converses regularly with everyone on their list. So bounces, spam traps and complainers are next to non existent and you’ll mail with no problems.
Now if your list is clean enough to be accepted by MailChimp and uploaded, then when you send out an email to your list , they still monitor it and mail out slowly to make sure your bounce rate is below their threshold. I am not sure what each white-listed servers threshold is, but it seems like its between 3-7% bounces are accepted over the various servers. So basically your list needs to be 93% -97% free of any invalid emails.
Invalid or dead emails can not be monitored when you upload your list, the only way to truly know if an email is valid is to send them an email. So if your list gets through, and your bounce rate ( hard not soft bounces ) is to high, then they stop your email campaign and tell you basically your list has too many hard bounces.
At this point you need to verify your list and get rid of the dead emails and resubmit the list and try again.
So basically if your going to send email through any of the whitelisted servers, they monitor everything, spam traps, litigators, role accounts, hard bounces, bad domains etc. So it only makes sense to fully scrub then verify your list against these same hazardous emails BEFORE you upload your list to any whitelisted server.
Now with all that said, you also have to understand that scrubbing and verification are not an exact science, its impossible to be 100% accurate for many reasons so even if you do so, the goal is to get you with in the accepted threshold range so you can mail out your data. White-listed server update their suppression lists daily and as new email threats are created daily its possible some get through and you might be 1% or 2% higher than a whitelisted server threshold, but your original list before scrubbing and verifying may very well have been at 70% clean list and we can catch that other 25-30%.
NO ONE can claim to be 100% accurate even the companies Mail Chimp and other white-listed server recommend to clean your data, so its important to fully understand this.
So bottom line if your cleaning your data to be uploaded to MailChimp or any other whitelisted server, make sure you scrub using as many filters and suppression lists as possible and THEN verify whats left over to be as safe as possible. This does not guarantee your list will get accepted, but in most cases it does.