That's an interesting one.
Don Mallinson, of DC Care Care and SHO fame, posted the following regarding car soap on his site
www.dccarecare.com:
Companies that have a vested interest in you buying their products have been spreading the word about all the damage that dishwashing soap will do to your car. Here is my take on all this.
The reason you wash a car is to remove dirt. To do that you need to do several things, most important is you need to make the water....wetter.
This may seem silly at first, what is more wet than water after all? Well, lots of things, but first and foremost, water has a thing called surface tension. This is what keeps water beading on shiny cars, and why you can fill a glass higher than the rim, up to a point. A good car wash soap will act to break down the surface tension. That is why soapy water doesn't bead.
Second, a wash soap must remove grease and dirt. It needs to be a detergent to do that, otherwise you are depending on the action of the wash cloth/mitt on the paint to scrape off the dirt. Not a pretty picture.
Third, a wash soap should make your paint feel slimy or slick, that means it is helping surround those bits of dirt/grease and let them rinse off your car.
I have tried lots of car wash products intended specifically for a car. Here is what I have found:
1. You CANNOT wash and wax your car at the same time. You can only do one or the other well. Any product claiming to do both is a compromise or worse.
2. Dishwashing soap does not "strip" wax off cars. I use Liquid Ivory exclusively on all my cars. Several national champions, 40 year old original paint, and daily drivers. The act of washing with ANY product will take a little bit of your wax off. That is what it's designed to do! Wax is supposed to slowly wear off to keep dirt from embedding in your paint. That is why Carnuba is such a great product. Every time you wipe, wash, rinse etc your car, you strip wax. It's going to happen no matter what you use.
Use a small squirt of Ivory Liquid in a bucket of water. You will get lots of suds. These are essential to helping get the dirt off your paint and away from your car without scratching. Any wash product that doesn't make lots of suds that last, is doing more harm than good. Most car wash specific products do not make good suds, and when you feel the wet paint it is not slick, but grabs at your hand. Ivory is slick and rinses clean.
