What is the best product to use as a car wash? The correct answer is use what you like the best. There are some drawbacks to certain products and advantages to others. Dish detergents (Ivory Liquid, etc.) may be used, but realize that these products are designed to remove animal or vegetable fat from fired ceramic. They look at your nice coat of wax with the same hungry eyes. If you enjoy washing and rewaxing weekly, then dish detergent is for you. Wax retailers love people who use Ivory Liquid (they send the Ivory Company Christmas Cards every year).