I have blue stains or marks on my white Macbook casing. Have read up about the problem and saw some people talking about a similar issue back in 2006, and 2008. The problem seemed to lie in faulty plastic being used, amongst other reasons and excuses given. Some people had serious staining issues and received replacement casings. My Macbook is a 2010 release, either Week 1 or 13 (hard to see on back), serial number beginning W801... Just checking what the prevalence is of this, how bad it may be with others, and if anyone has had company/other advice on the issue?