Ruby on Rails app fetch bounces How to?

is there any possibility to check with the ActionMailer mail function if a mail-address is still alive?

My problem is that I have a ruby on rails application with lots of users, but some of those changed their mail address and now I got lots of mails back. It would be cool If I can check if the mail is still present, and if not I delete the user from Database.

Any Ideas for this problem?