Question: Will [a] decal harm [the] painted surfaces of my vehicle? Answer: No. In fact, it provides a sunscreen to your vehicle’s paint, which is why we don’t advise you to put decals on your car’s painted surfaces unless they’re permanent. If you put a bumper sticker on the painted surface of your trunk, for instance, and remove it 3 years later, the other paint on the vehicle may have faded somewhat, but the paint under the sticker will be a little newer looking and less faded.