There is already a way for the community to get rid of truly bad accepted answers, without help from either the OP or from ♦ mods:
Downvote the answer until its score drops below zero.
Get three users with 20k+ rep (2k+ on beta sites) to vote to delete it.
Technically, the answer will still be accepted — but once it's deleted, it will no longer be visible to most users, and will be clearly marked as deleted for those who can see it.
So how do you get all those people to downvote and del-vote the answer? Well, the first step is to post a comment on the answer explaining why it's so bad, if only to discourage more people from upvoting it in the mistaken belief that it's correct. If there isn't already an alternative answer offering a better solution, and explaining why the bad solution should be avoided, I'd also recommend posting one.
After that, I would point you towards chat.
There's a link in the top bar menu (and in the footer) on each site to the chat rooms associated with that site. Most SE sites (and most major tags on SO chat) have more or less active chat rooms where you can ask for help with matters relating to the site, including asking others to visit a post and vote on it. (Yes, as long as the other people are free to make their own decisions on how to vote, this is perfectly acceptable.) In many chat rooms, it's common to tag such requests with a "fake" tag like cv-pls / dv-pls / delv-pls, especially where the reason for close/down/delete voting the linked post should be obvious, but feel free to phrase your request any way you like.
If chat doesn't seem helpful, or if your site just doesn't have enough active chatters, you can also post on your site's meta. That's a tried and true method of focusing a lot of attention on a post.