Fit and top management, but unfortunately over time increasingly discolored

I had this protective cover for about three months in operation. Basically, I was very pleased: It fits like a glove on the iPhone 6, the mobile phone can be sufficiently insert easily and also found again when needed, without having to fear damage to cover or even device, and the grip of the sheath is my feeling after outstanding: sufficient grip to hold the phone securely with one hand and use can, but not as "sticky" as some soft silicone or rubber holster.
Also it does not take on so much that you feel after the application has to keep a much larger compared to previous mobile phone in hands.
Negative I have to say that the case has started after a few weeks of use to discolor unsightly, principally in the areas that have the most contact with the hand, however. I would imagine that this is possibly caused by sweat or maybe. By residues of hand cream, the use of which may be attached so well already, especially in the winter months However, these are only speculations. Anyway, I have this product initially so preferred to others because I wanted to see something of the rear panel. A beautiful sight, however, this is only as long as the transparent plastic is simply more neutral transparent and does not have a more expectant yellowing. A washing the shell has not incidentally, helped not with pure water, even with additional cleaning remedies.
Ultimately, I have but then resorted again to a black envelope with otherwise similar characteristics and waivers since the yes also not so important look at the back of the iPhone.