Nov 20, 2018· The Model 3 manual states use "a mild highquality car shampoo." There were plenty of "car wash" choices at Pep Boys, but nothing labeled "shampoo" and the salesman, who didn't really know what to use, did say that all the washes have detergents. Any suggestions of safe products to add to water to hand wash? For other cars, I've always added a squirt of dish soap to a bucket of water, but .