OK, can someone atleast please recommend a type of polish that can get rid of this smudge?

Ok I updated the link

I dont think it became hot cuz it was like that before even turning the phone on. Anywayz i dont think etisalat will change it for me cuz they r always out of stock and this barely visible mark wont justify an exchange.

I recently purchased a new iPhone 4 from Etisalat in UAE. And I noticed there is a smudge or like a burnt mark on the low left side of the phone (where the antenna is located). I am just wondering if anyone who recently purchased a new iPhone got the same mark? Screenshot: