I had a client I picked up 3 months ago, that had a previous SEO firm that was obviously doing spammy bs links. Spun blogs, unrelated blog comments, jibberish content links etc. He was well aware and that's why he switched over to me for more quality links. So far I have created web 2.0s with hand written articles, paid directory submissions and a press release. His site was slapped into oblivion after this latest update to page 7. I really doubt any link building I did had to do with it, but he did have hundreds of spun crap links to his website from the previous company. What is the best way to explain this to him?