Any “whitelist arrangement” between an ESP and ISP is instantly revoked by the high level of spam complaints that result form purchased lists. ESPs do not have any special, official arrangements or handshakes with ISPs. They monitor incoming traffic from us, just as they monitor incoming traffic from you. The only thing I’d say ESPs have in the way of special relationships with ISPs is that they usually know who we are, and so are more comfortable using curse words with us when they tell us how stupid some of our customers are behaving. “Go tell your idiot *$%# client to stop sending to this obviously purchased list, before we block all your IPs.” So yeah, most ESPs would suggest that people with purchased lists jeopardize their *own* servers’ deliverability, instead of ours.

Re: phpList or scripts to wash your list, that’s not what I’m recommending. I’d recommend manually emailing to your list, one by one, explaining to each one of them how you obtained their email address out of the blue, and why you think they should subscribe to hear more from you. In some cases, a company becomes a member of an XYZ organization of professionals, or sponsors one of XYZ’s event, and XYZ gives the company a list of their organization members. This is the most common reason we shut senders down. In this scenario, the company should never use MailChimp (or any ESP, imho). Ethics aside, this approach just won’t give you any results, so it’s stupid. What you do is you ask the XYZ organization to send an email (this is where *they* could/should use an ESP) telling members about you and your list. Actually, that would suck too. Nobody wants an email ad promoting another email list. So you’d need to come up with something really valuable to the members. Like a free research paper of some sort (depending on the audience, maybe it’s more like a free t-shirt, I dunno). Have the XYZ organization *give* that prize to all their members, and *then* maybe you’re on to something.

There are legitimate ways out there (albeit few) to turn a purchased list (not the “2 billion opt-in emails from this CD-ROM in Russia” kind) into something somewhat useful (though the list will be composed of short-term, non-engaged freeloaders). Using an ESP because it has a whitelist arrangement is not the silver bullet though. In fact, it can set you back and put a company into an even worse situation than the one that made them consider purchasing an email list in the first place.

Not worth it, imho.