This can be a tricky process to navigate, and the solution will vary with every specific situation. We suggest that the company engage a good ESP or Deliverability consultant to assist, and that legal counsel also be consulted if appropriate. Data protection laws exist in one form or another in more than 70 countries, and they are very often applicable to email marketing. There are many avenues that can be taken to address this situation, once of which is a “re-permissioning” pass. A Permission Pass involves sending out a new bulk email to the problematic list, asking the recipients to confirm that they wish to remain subscribed to it. **Only those who confirm are then kept on the list.**Those who do not answer affirmatively (or whose addresses bounce) should be flagged as “do not mail”, or whatever makes sense for the platform in use. The resulting list will be a clean, 100% Confirmed Opt-In list that provides a low risk, high ROI method of reaching clients.