Some years back C/D had an article where they interviewed a car detailer. Guess what he used? Ivory liquid. Of course, he’d then go on to wax the car.
The chemist in me wonders how a car wash detergent can work on only dirt, but not wax. Same thing going on in both cases…
If you can find this product called DRI Wash N Guard. I had good luck with it. It works to a point. I used it on boats in the cockpit areas of sail boats and on the bridge of power boats. It great if you don’t want to use a lot of water. One of my customers claimed that his gold rings would not leave marks on the gelcoat after I used it. It does seam to make a dull car shine. But any good cleaner ( Very light duty compound ) and good wax is all you need. As test once I used different brands of car wax on sail boats that were in the water for 5 mo’s. All would bead water when they were taken out. I could not tell if any of the wax were better than the rest. All the boats cleaned up easy.
Chemistry was never my forte, but the question is interesting. Perhaps both are really just mild surfactants that break the surface tension but don’t in any way attack the structure of the cured car wax.
I think we had a chemist post recently. I’d love to get a chemist’s input on this.
From my own standpoint, I only ran application tests with the products I used. The tests were conclusive, but only for those exact products.
@DfromSD…when you say…paint in good condition, well, it is 21 year old paint. It has some minor nicks here and there, other than the side where it had been painted by a body shop after someone sideswiped us, where it’s splitting and peeling near the window. I always treat this area gingerly. Yes, I need to get the peeling parts fixed but the place is out of business so the lifetime guarantee is for naught! 
Yes, I’m a chemist.
Read up on dish soap used as a car wash and you will be told it dissolves natural oils and waxes. True. But who waxes with carnauba these days? Who wants to rewax every month?
Modern car waxes use synthetic materials. When applied and dried they polymerize. That means your paint is encased in a thin film of plastic. Plastic is not fazed by Dawn, Ivory, etc., as millions of car-washing folks already know.
So those who still choose to forgo dish soap because of something Grandad said many years ago are welcome to do as they please. Suit yourself.
At least we agree that dish soap will not harm paint, which was the remark that provoked my original response. Can we drop this now?
If the rest of the car is in good shape perhaps MAACO is an option. In my area of the country they have specials for $249 that include cleaning and prepping the finish. It’s an overspray, but the MAACO up here does a pretty good job. It can be a great way to give a facelift to an otherwise good vehicle.
Steve, thanks for posting in. I’ve learned something . It’s a good day.