You have collected thousands of opt-in email addresses from your website and added them to your mailing list without properly verifying if the address owners actually consented to be subscribed to your list. You sent out a bulk mailing to the list and now you're blacklisted by ISPs and spam filter systems for spamming. How can you now fix the problem?
The solution is to conduct a Permission Pass to rid your list of those addresses which should not be on there. A Permission Pass involves sending out a new bulk email to your list asking the recipients to confirm they wish to remain subscribed to it. Only those who confirm are then kept on the list, those who do not answer (or whose addresses bounce because they're filtering you due to the previous spam, or never actually existed as users) are deleted from your list. The resulting clean list is a 100% Confirmed Opt-in list, infinitely more valuable than what you started with.
Before conducting a Permission Pass you need to liaise with any major spam filter systems that are currently blocking mailings from you, agreeing the mailing in advance. Spamhaus for example will normally agree to help you if they believe you are honestly converting to COI mailing, by lifting a specific listing (or not listing new IPs) to allow you to conduct the mailing without hitting SBL spam filters.
It is however vital that you understand the semantics of a Permission Pass:
A permission-pass is only appropriate where an otherwise Opt-in list has got slightly dirty - not one that has been gathered by harvesting or from other questionable sources. You can not simply buy a list from a 3rd party and conduct a permission pass on it, you will simply be considered to be spamming and treated as a spammer.
A Permission Pass is opt-in, not opt-out. You can not ask recipients to respond in order to opt-out of the list, as that is no different from ordinary spamming. No "permission" exists with opt-out and additionally recipients can't opt-out of something they do not receive. Opt-out leaves all the bad addresses on your list, leaving you open to generating complaints, hitting spamtraps, and continuing the cycle of mailings ending in julk folders or blocked by spam filters.
A Permission Pass will significantly reduce the size of your mailing list, by anything from 50% up to as high as 90%. This may at first seem counter productive to some marketers who think volume is better than quality, but there is no point in having a giant list of people who are not responding or who feel they are being spammed.
You can only conduct a Permission Pass once for each recipient. If they do not respond you can not contact them again to urge them to respond.
The resulting clean list is 100% recipients who are interested in receiving your mailings. Keep it safe from future pollution.
If you are really serious about the future of your legitimate bulk email marketing business, consult an email deliverability specialist such as word-to-the-wise.com who can help you devise ways to not just mail responsibly but also to be seen as a responsible mailer by the Industry.
Reference & Courtesy: Spamhaus