I had Invisible Shield installed on the back and sides only of my white iPhone 4s back in November. For the last few months I've noticed black finger type smudges all over the back. It's absolutely ruining the beautiful look of the pristine white . I'm supremely careful with my phone. I keep it in a padded pocket in my purse and I rarely ever touch it if I haven't washed my hands first. I've tried cleaning it with glass cleaner from apple but no luck. Has anyone else had this problem? I'm hoping it's the shield and not the phone - eep, now I'm freaking myself out, lol. Thanks! *sorry for the spelling in the title. My sleepy brain is not functioning right now.