Any one else experience white streak on drive side back panel picture below. We had long winter here in Ohio, so through it might be salt residue. However didn't come off after a car wash. So last weekend I got out the clay bar, and then hand wash it , but still unable to get this to come off. What's the best way to clean/treat? Should I use something like Scratch X on it? I'm not sure if the issue with the clear coat or the clear bra that on it.