My questions are, is there any legal way I can add these emails to a list with an email list service? Can I legally opt them in since they made initial contact, or can I at least send them an email with an opt in offer?
Hi, if you’ve already done business with your clients before and they have already contacted you in the past regarding your services then adding them to your mailing list should not be a problem.
I use Aweber which allows you to import email addresses to build your list of contacts.
When you add them, an email will automatically be sent out asking them to confirm their opt-in.
If you need help managing your list and getting the most repsonse from them here’s a very useful site below..