Thanks for all the input, I had a retail website where most of them signed up for sales and newsletter emails, I don't have that website anymore

my ex husband has it now and its non existing. I do have the list and basically wanted to promote my new website using this list. I was thinking about using the facebook approach but I may not get new customers that way so I thought of sending an irresitible offer $19.99 "niche product" that is reg $60+. It is possible the 2nd option of the email deal will not result in customers so I was going to use the fb page as a backup. What do you think about that?
A few years back when I did black hat selling I had a smaller but more targeted email list that when one site when down or if they did not like the quality of product or customer service I would email them from a new email introducing another website. I never really has people opt out maybe of 5k 3 people. I do not spam Viagra offers or anything like that. Now, how can one prove they never signed up for a newsletter after all anyone can create a sign up via there website, or am I wrong?