Keep a close on your backlink profile. Check it periodically.
Make sure you audit it on a regular basis. If you need to remove the links, contact the webmasters and ask them to remove the links from their sites. Do this at least 3 times. Note everything down as this will come in handy later if you need to send in a reconsideration request.
If you have a letter from Google for "unnatural links warning" then you definitely have to go the reconsideration request route.
When auditing your backlink profile, you can go straight to the disavow tool if you have n't received a warning from Google.
Make sure you do this on a regular basis - like taking out the trash.
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