Hide e-mail address from guests

[nrep]

We're running an old forum which has some e-mail addresses posted as plaintext in forum posts, and I'd like to filter these from appearing to guests (so they they aren't harvested by spambots).

I've been struggling to find a way of doing this, but I'm sure that it must be possible to have a regex run somehow at the time of displaying posts (a little like the censorship option).

Has anyone done this before or knows where I could start?

 

[nrep]

I forgot to mention, I've found the regex to use (http://www.regular-expressions.info/email.html), but I don't know how to apply it .