How old is old? Have you been in communication with these people on a regular basis?

- If yes, you could send an email to introduce your new company/product. Best practice would dictate that you ask them to opt-in, but in this case you could do the reverse and ask them to opt-out of future mailings since they know you already.

- If you don't have an ongoing relationship with them, you could send a two-part email series introducing your new product and asking them to opt-in. You can also disclose that they purchased something from you in the past so they know why you have their email. As your send the email series, eliminate all non-responders from your future mailings. Allowing your old list to proactively opt-in ensures that you will have engaged prospects on your new list, and allows you to eliminate bad email addresses and avoid low engagement from people who haven't shown interest in your new product - two key reasons for ending up in the spam folder or worse undeliverable.

If you'd like to chat more about how to structure your emails, email best practices or maintaining high email deliverability, let's schedule a call.