Like bad backlinks showing up in search engines? Or links located on your site? Be more specific, please...
Google webmaster is an option to delete bad links. It lets you know your broken links and as well as bad links.
That's up to the webmaster. If he or she doesn't fix it, there's not a thing that you can do about it. If the site is operated according to standards you should be able to reach the webmaster by addressing an e-mail to webmaster @ whatever the domain is. That said, a site full of broken links probably isn't being monitored so you probably won't get any response.
I think you have to email to website owner to remove your bad or spam links. because Google don't do it self.