If the answers are just wrong, you can downvote them. If they are unrelated, you can flag them for moderator review. (Not-an-answer answers appear to get vaporised very quickly, once someone finds them.)
Check the Unanswered display -- it shows both questions with no answers and questions without up-voted answers. I don't know how many users actively read this query versus the main [Questions] query, but hopefully it is enough to help garner new answers among users not in the The Fastest Gun In The West club.
