It’s completely normal to have links from external websites which are not related to your industry, no action required. You have to ask yourself, why would Google penalize you for this? The only danger is buying links or getting links from link farms or low quality spammy websites in large quantities, or low quality foreign language websites with spammy anchor text etc.
Google webmaster show warning and give massage in manual sections. so basis of manual action we can decide which type of penalty our website have, if your website has penguin penalty so we have to find out and filter spam backlinks of your website. We have to filter spam links, all links appear in Google webmaster which have link to your website.
If there are hundreds or thousands of them with identical anchor texts, you should use Google’s disavow links tool.
We have to keep some below points to filter spam links.
Links from penalized website
Porn and other spam website link
Links from paid sources
There are 3 great tools for assessing the quality of your backlinks.
Majestic.com will give you a list of most backlinks and an insight into their quality. You can export their lists into LinkDetox and their reports will tell you about sites that are outside the Google index, part of link rings, from suspicious neighbourhoods etc.
LinkDetox will help you create a disavow file for Google. And help you to analyze risk of new potential links
www.rmoov.com:- If you need to do some clean-up work, Rmoov has a great tool suite for sending emails to site owners. It’s the only way to stay sane if a client needs a big backlink clean up job.
We regularly run this process for a client who used to have around 50K backlinks and LinkDetox reported 90% were suspicious!