This week on The Best of Car Talk, Jim thought he had a disaster on his hands after he left his gas cap off during a rain storm, but his pal came to the rescue by pouring mothballs into the gas tank. Can Tom and Ray give any explanation for why the mothballs got Jim's truck running? Meanwhile, Ray's got a theory about Heather's Jeep's popping noise that may win points for creativity and bogosity. Also, Patrick hopes the guys can help him design the perfect soapbox derby car; Ann needs assurance that putting a new engine in her beloved Fuego isn't the most ridiculous idea ever; and has one of our listeners identified the true scent of a man? All this and more, this week on The Best of Car Talk.