I'm very mistrustful of professionals who strongly recommend the products they sell, like car washing detergents and cleaners and at the same time disparage other cleaners like gentle dishwashing liquids. After all, we have to be careful washing dishes because if dishwashing detergents were too strong they'd damage our lovely skin. I have a 30 year old Lincoln Town Car that I've been washing with dishwashing detergent for as long as I've owned it and it's finish is just as beautiful today as it was when new. Compared to the hot sun, bird droppings, squashed insects, rains, dust storms, ice and salt, smog, corrosive exhaust fumes from the cars and trucks ahead of us, acid and particulates in the atmosphere and the hidden cleaners in waxes and polishes, I wouldn't worry too much about a sissy dishwashing detergent utilized in a weak solution. In fact, most of the time a car can be cleanly washed with just water, lots of it and a terry cloth then dried with a (not new) chamois or turkish towel. There are many new polishes on the market (without hidden cleaners) intended for the clear coat finishes used on new cars today. Clear coat is intended to make cars look brightly polished without waxes and stuff. Clear coat is excellent and tough. It just can't take being rubbed by somebody elses' fender, that's all.