Vinyl graphics (just like paint) are degraded by prolonged exposure to sun and atmospheric pollutants, particularly on the horizontal surfaces such as hood, trunk lid and roof. Whenever possible, store in a garage or at least in a shaded area during the day. At night protect the car from dew or rain, which may contain acidic pollutants (a common problem in many large metropolitan areas). When a garage is not available, consider using a cloth car cover at night. If your graphics start to discolor or turn brown, immediately remove the graphics from the vehicle to avoid staining the underlying paint.