Historically, it has been said that oil/grease (such as from fingerprints) residue on optical media (CDs, DVDs) can damage the discs over time by degrading the polycarbonate surface, eventually rendering the discs unusable. Well, I'm wondering if this still holds true for the blu-ray format? All blu-ray discs are supposed to be protected with a scratch-resistant, anti-static coating. Does this coating also protect the disc from foreign substances (such as oils or chemicals) from contaminating the disc and causing it to physically degrade over time? In other words, will greasy residue (or some other kind of harmful substance) break down the special coating that blu-ray discs have like it would a CD or DVD? Or does the coating also provide protection against that?