hello, I am going to be painting a white cadillac with 3 rust spots. I am no stranger to car painting, but I wonder if I can do a touch up on this (repair rust and prime/basecoat the repair spot) and clear the whole car. with it being white I am worried that dirt will hide in the finish. Is there any way to prevent this, or am I just better off basecoating the whole car with fresh color and then clear it. Thanks.