Admitting that the cause of the discoloration some MacBook owners have seen is the result of a manufacturing defect, Apple has said that it will arrange to replace affected laptopsi cases with new ones. Previously, some of the companyis AppleCare representatives had attributed the issue to a cosmetic problem caused by improper handling, which is not covered by warranty.
According to ZDNet: "It appears that the original MacBook plastics were too porous which led to staining after oils become embedded in it from prolonged use. Apple changed the formulation of plastics in the production line already, so the newest models arriving in retail stores shouldnit have the same problem. The newer top case is reportedly much smoother to the touch than the previous MacBooks which feel slightly rougher."