Dawn or car shampoo?

I have been hand washing my cars with Dawn dish soap as long as I can remember. I recently came across the considerable debate on the Internet about using household products versus specialty car shampoo. I even read that Dawn is considered an abrasive.

It seem to me that if Dawn is gentle enough to clean oil off live, baby ducks, it would be OK to use on a car. What do you think? Is there a milder household product that will remove the dirt without harming the paint?

It’s my understanding that most household cleaners, remove the wax from the cars finish. That removes the protection from the clear coat or paint. I know Dawn is good at cleaning greasy hands after working on a car. Don’t know specifically about car waxes.

The reason dawn is used on waterfowl that have been exposed to oil slicks is that it is a very effective degreaser. That said, ducks need oil on their feathers (produced in their preen gland near their tail) to shed water off their feathers. I do not consider it an optimal choice for waterfowl or other birds that simply need to be cleaned.

I suspect it is less harsh on paint than on feathers, but feathers molt and regrow. Paint doesn’t.

I used Zaino to wax my cars and their instructions were to wash with Dawn to remove the old wax. The car shampoos won’t do that.

When you wash your car in your driveway the runoff ends up in the storm sewer which flows to a nearby waterbody (assuming you live where there are storm sewers). Products designated as car wash are biodegradable. What I’ve read about Dawn is that it isn’t good for environment.

Wow! Much to consider here. I worked for two environmental engineering companies. One specialized in wastewater and it never entered my mind that washing a car at home may not be good for our environment.

My car is a 2005 Toyota that I bought new. I have never waxed it and the paint looks about the same as always. Now, if I could just do something about the yellow headlights.

Thank you to everyone.

Yellow headlights-a fine abrasive will clean the surface which often is the cause of the yellowing. Try a small corner spot to test. A mechanic friend of mine (retired shop owner now) used toothpaste-there is grit in it. Auto parts houses also have commercial polishes for the lens.

Most opaque white toothpaste has a little bit of polishing compound in it. it also works to remove small scratches on wristwatch crystals. Or you can also try the polishing compound used to create that shiny lacquer car finish look. Also jeweler’s rouge will probably work.

I know of no abrasive liquid product that is transparent. I can see thru a bottle of liquid Dawn dish soap. It is a solvent and a surfactant.

People still wash their own cars? [car wash five minutes away–have not washed a car in decades]

Good outdoor exercise. Save a buck or two. Pride in knowing the job was done right.

I still have to think about the environmental impact. I did environmental site assessments for real estate transactions in the 1990s. I cannot remember evaluating a car wash but I do remember a quick change oil business who was contaminating soil and groundwater.

So who pollutes more, the guy who changes his oil at home and spills a little before taking the oil to Walmart for recycling or the oil change place that does not really care how much oil they spill? What about the guy who takes his oil out back and pours it in the creek?

I have tried toothpaste. I polished by hand and it was a lot of work. It looked OK for a few months. I heard that you can use wax on plastic headlights.

I read about Dawn being an abrasive in an Internet article by Consumer Reports. I don’t put as much confidence in CR today as I have in years past.

Abrasives have tiny particles of solid matter with sharp edges. They work like sandpaper, the tiny particles gouge out microscopic chunks of what you are abrading. If the abrasive particles are small enough the gouges are shallow and so close together it leaves a shiny surface. When you polished the headlight lens you removed the thin oxidized layer that had turned yellow. Then, as the newly exposed plastic surface oxidized, it turned yellow. And because the little scratches added surface area to the plastic lens surface the color will come back darker that it would on the original smoother surface.

If Dawn dish soap contains any abrasive particles I sure can’t see them. Even if there were, they would be so small and widely dispersed that it probably wouldn’t have a visible effect on washed surfaces. I suspect the rumor has it’s origins in “studies” or “research” sponsored by the car-care products industry. Liquid dish soap works because it is an effective surfactant. It sticks to hard non-porous surfaces and gets between the foreign matter and releasing it’s grip, it doesn’t cut out grooves like an abrasive product does. Comet cleanser is an abrasive.

Wife washed our eyeglasses with Dawn and warm water for decades. Never saw any bad results.

Back in the 1990’s, during a long-haul flight, I sat next to a young man who had just finished his doctoral thesis and interview. He was a tribologist, and his thesis centered on nano-tribology. the science of friction, wear and how two surfaces interact at the nano level when they move against one another.

It’s a fascinating subject: