One of the main goals of SEO is to increase the number of relevant sites to link to you, because that can help improve your rankings. What happens though when a site that isn’t relevant or from a gambling or adult site links to you?
These links could be decreasing your own rankings!
To address this Google released their Disavow Tool as a method of informing Google to not count these backlinks
The Disavow Tool allows you to specify to Google which backlink URLs to remove as a ranking factor. This is achieved by creating a defined .txt file which lists these domains
When you first access the tool, you will be presented with a fairly strongly worded warning before you progress!
This is an advanced feature and should only be used with caution. If used incorrectly, this feature can potentially harm your site’s performance in Google’s search results. We recommend that you only disavow backlinks if you believe that there are a considerable number of spammy, artificial, or low-quality links pointing to your site, and if you are confident that the links are causing issues for you.
You should consider using the disavow tool once you have used the usual routes of trying to get links removed off your website.
Disavow is also perfectly suited if you are suspicious that someone is undertaking negative SEO and you are receiving a number of suspicious or low-quality backlinks that may hurt your rankings.
If you have received a manual penalty from Google then you must use the Disavow tool to assist in the removal
To use the disavow tool, first you need to download links to your site (for more information please read https://support.google.com/webmasters/answer/2648487?hl=en)
Download links to your site
On the Webmaster Tools home page, click the site you want.
On the Dashboard, click Search Traffic, and then click Links to Your Site.
Under Who links the most, click More.
Click Download more sample links. If you click Download latest links, you’ll see dates as well.
From this file you then should create a txt files that contains ONLY the link you wish to disavow, one link per line. For example the file would look like:
# strangesite.com removed all bar 2 links
# Contacted owner of imhurtingyourseo.com on 7/1/2016 to
# ask for link removal but got no response
Then as per Googles instruction you would then
Upload a list of links to disavow
Go to the disavow links tool page.
Select your website.
Click Disavow links.
Click Choose file.
This file would then replace all previously uploaded files, it can take some time for this information to be processed.