Krakken OCD's summary of how to clean your car.

[LastStep]

If you want your car to look amazing without a ton of effort or expense, here's what you should do.
Twice a year, follow this cleaning and sealing process:


1. Clean it.

Cleaning means getting to the point where there is nothing still sitting on or stuck to the paint.

• Rinse it.
• Wash it using the two-bucket method and a microfiber wash mitt. (Two-bucket method = one bucket for soapy water, one bucket of plain water to rinse the wash mitt and get the dirt out of it). You might use Dawn detergent at this step (see below). Note that your hose should be turned off at this point. No need to waste water.
• Rinse it again quickly to get the suds off
• Dry it, preferably with a microfiber waffle towel
• Clay bar it with lube. The claying step is critical. It's amazing how much **** is still stuck to the paint after you wash it. The clay gets rid of this embedded junk. I prefer a newer type of synthetic clay sponge than actual clay, but the process is the same for either.
• Wipe it down with a 50/50 mixture of rubbing alcohol and distilled water. This removes the clay bar residue, as well as anything still lingering on the paint. It does not leave any residue, which is what you want.

Once you're done with that, the paint should be absolutely clean and smooth, with no grit, sap, stuck-on bits, residue, or other contaminants. It should feel like glass.

2. Now you're ready to seal that nice clean paint. I use the term "seal," instead of wax, because technically wax comes from a tree, and the product you're most likely going to use is a synthetic sealant. The point of a sealant/wax is to coat the paint with a thin layer of bonded slick transparent material that protects it. A properly sealed paint surface will be easier to clean because contaminants can't stick to the slick surface as well. It also helps filter UV rays that fade the paint. The slickness also creates a shiny effect which is what most people think a sealant/wax is for, but I think the most important thing it does is protect the paint. Modern sealants apply in a thin layer and buff out very easily by hand with a microfiber towel.


3. Now treat the rubber and plastic parts (non-painted) with an appropriate product. You're done. Your car should look awesome.


Once you're done, you can regularly maintain the finish with the waterless wash spray-on. This should take no more than about 15-20 minutes for the whole car. The more often you do this, the easier it will be, because less dirt will have built up in-between wipe-downs. Once it's clean from the waterless wash, you can do an optional quick wipe down with a synthetic detail spray that adds slickness and helps preserve the sealant protectant layer.


Here are some brief points as well as answers to the questions that came up in this thread:

• Improper washing causes scratches. Why? Because most road dirt isn't dirt in the sense of soil or mud, it's actually bits of rock -- sand or fine gravel. Those little particles of rock are harder than your car's paint, and will scratch it. Washing the car in a way that doesn't lift all of these rock bits away from the paint surface (such as a commercial car wash or a dirty hand wash mitt) rubs them all over the paint, causing fine scratches called "spiderwebbing" or "hazing." Over time, the paint will build up enough scratches that it's not as shiny anymore, and can even wear through the clear coat in spots so that the color layer is no longer protected from deterioration.
• Commercial car washes: I'm not a fan of the drive-thru drive type because they don't clean all of the exterior that thoroughly, and they leave scratches. Those swirling brushes trap dirt (rock bits) from all the other cars that went through there.
• Undercarriage wash: these are just just water nozzles pointed at the bottom of your car. They won't hurt anything, but there's no way they are going to remove all of the salt and gunk from every spot under there.
• Car wash "wax treatment." Laughable. At best, this is some liquified silicone or polymer that will make the car shiny for a few hours, but there is no way it's actually bonding to wet paint to provide protection. It probably gets your windows all greasy too.
• To answer the question about why you'd even bother cleaning the outside of your car: one, because maybe you like your things to look nice, and two, you want to maintain and help preserve the value of your things, especially expensive things like cars (or even cheap cars). There's no doubt that a used car with a well-maintained exterior will fetch more money at resale than one that's been trashed. Or maybe you don't want to make your clothes filthy just because you brushed against your car.
• No water = no rust concept. If you're Jay Leno and have a fleet of collector cars in climate-controlled storage this is true, but for the rest of us, unless you live in the desert, there is no way to avoid getting water on our cars. Even the humidity of a NY state summer or dew on a sunny morning is enough to promote rust on bare ferrous metal. For normal daily driver cars, the big enemy is not tap water from a hose, it's salt. (It's not the 70s anymore; car manufacturers have figured out how galvanization works by now.) Sodium chloride is an excellent oxidation catalyst. The best thing you can do is get the salt off every part of the car using, yes, lots of plain water. Rinse the hell out of the underside. Plain water alone will not cause rust on a modern car if it has a chance to dry; the salt is what tilts the chemical equation in favor of oxygen so it can defeat rust-deterrents like galvanization. Rinse as much of that salt off the underside as you can, preferably with a hose, on a dry day so the water has a chance to evaporate. Normal hose pressure will NOT hurt the engine or other major parts. I've been rinsing engines for years with no negative effects. (Obviously, don't take a power washer to the air intake or spark plugs or ECU.) If you're interested in learning about undercoating products that may help deter the salt-induced corrosion, I have some thoughts.
• "Washing the car also removes the wax." No, a good quality hand wash product will NOT remove wax or sealant. Nor will a good waterless wash product. Yes, a commercial drive-thru car wash probably will remove wax or sealant, because it's basically scratching the **** out of the car, and those detergents might be caustic. Note that Dawn brand dish detergent WILL remove wax or sealants. It will strip almost anything oily off a surface. It's used to clean sea birds that get coated in oil from tanker spills, for example. If you know that you're going to do all the cleaning steps then seal the paint, Dawn is a good choice. Otherwise, use a mild auto-specific shampoo that won't strip the sealant/wax.

If you're actually interested in doing any of this, I have a list of cost-effective products that I've tested and can confirm work well.