This is a two-step process. First, you’ll need to download a list of links to your site.
Next, you’ll create a file containing only the links you want to disavow, and upload this to Google.
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.
After that Disavow from Google webmaster tools is one way to remove bad links
Go to the disavow links tool page.
Select your website.
Click Disavow links.
Click Choose file.