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I just want to ask your advice or suggestions, my new client site received a link warning from Google regarding unnatural link, as I've checked his site backlinks using Seomoz site explorer there are almost 4000+ backlinks and almost 3/4 of the total links are from forum profile spam and blog comment spam. I know it is impossible to remove all those links totally. I would like to ask your advice if what's the best thing to do? Setting up a brand new site and domain or doing a cleanup. Thanks in advance.