For those of you who have this case on your iPhone, especially on the white iPhone 4, have you experienced discoloring of the case after a couple months of use? I am on my second clear frost case after the first one I purchased became yellowish in color. Although the main reason I had to get a second case is because it broke in the corner near the camera. I just wanted to see if I was the only one experiencing this, or if others had this issue too. I'll probably go to the black frost case if it happens with my second clear frost case.