TooFineAPoint said:If you have a product to sell, send out a re-engage email to see who's interested.
Break your list into smaller segments, based on the demographic you think this product would be most helpful for. Start with 5 sets of 2000. Start 5 free Mailchimp accounts (2000 list members are free in Chimp).
Make the email really simple, like an opt in. Think of it like a cold call over the phone. Really brief -- are they interested in hearing about this thing that might help them. Segment any of the positive replies in Mailchimp, so you can easily identify and sell to them in the near future.
Make the email just simple text, and make sure the subject line is not spammy at all and looks like a personal email from a friend.
After an initial run of 10000, you will see if your list can be re-engaged and sold to. If you can generate a little profit from that run, it is worth paying for a serious email program to run through the rest of the list.
This method I described might take you a few weekends, if you have a product ready to go, and it's all free.
If you are new to this, check out the book Boron Letters by Gary Halbert. You could easily read that in a few hours.
It's true what the others are saying, that it's better to have a properly vetted and engaged list, but you could be sitting on some money here, or at least a great self-study course to teach yourself email marketing.
Hi, thank you for your advice, I'll take a look to the book you suggested to me and I'll try to follow your advices.