I have a proton waja for around 6 years. Now I want to peel off the doorside sticker. But I tried peeling for the first time, it seperate into two layer which is the sticker & the printed transparent. Now the printed transparent came off, but the sticker still sticks on the door. I bought Goo Gone, tried following the directions. But cant peel off. How to use Goo Gone? Any other suggestion/opinion?