This week on Car Talk, does a clean car get better treatment from mechanics? Leif in Pennsylvania has been conducting field research, and has some expensive evidence that supports his theory. Elsewhere, Lancelot just got home from Burning Man with a souvenir he didn't ask for-- the alkali salt dust now in every pore of his Pathfinder. Also, Karilee's about to say, "I do", but needs help convincing her fiance to say, "I will buy you a Volvo"; Kurt's looking for a way to eek out a few more cool days from his dying air conditioner and, in honor of the Puzzler's return, we ponder the many definitions of bogosity. All this and lots more, this week on Car Talk.