There are 2 competing businesses in my area. I am not going to mention what they sell, but let's just say they are in the services industry. I am a client of one of them. Well, the other day, the girl that works there sent all of their clients (including me) an email. she forgot to do BCC, she sent it as CC. Now I have all/some of their clients email addresses. how to monetize? can I sell these to the competing business?