This function can be used to delete those email addresses from a list of email addresses that do not wish to receive emails or that should not be contacted for any other reason. This requires a second list, the blacklist. This can contain entries in the following format:

• a complete email address that is to be blocked
• '.tld' => all email addresses with this top-level domain will be blocked
• This email address is being protected from spambots. You need JavaScript enabled to view it.' => all email addresses with this domain will be blocked
• This email address is being protected from spambots. You need JavaScript enabled to view it.' => all email addresses with this sub-domain will be blocked