[creativesquad]

Identifying a bad link is challenging because there is no set method that we know of by which Google will decide whether to penalize a site. Indeed a few “iffy” links may even be helping your rankings, you can never be sure.
Unless you already have a penalty hanging over you, or know that you have been doing something you shouldn’t it is best to be cautious and only hunt for the very worst links for the time being.
It is also best to this manually, because the last thing you want to do is start trying to remove links that are actually helping you. Unfortunately that can take some effort