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).
Below are the listings of manufacturers and exporters of car care products.
Lately I have been using Palmolive to clean bug residue off the front on my car as well as the grit that seems to get thrown up right behind the tires. It works great and I have yet to see any damaging effects to the paint. I do rinse it with water quickly and well.