Clay Bar Basics
The first thing I will recommend is that you wash your vehicle well in a shady or covered area! Use the two bucket method. One bucket with your car wash solution, the other bucket with just plain clean water. Use a genuine sheepskin or wool wash mitt and try not to use a sponge! Sponges trap dirt at the surface where as the wool mitts will hold the dirt up and out of the way!
So...rinse your mitt in the plain water bucket and squeeze the excess water out, now dip into your wash solution and wash a section of your car. Now dip your dirty wash mitt into the plain water to rinse the debris and then back into your wash solution! You get the drift of this by now I'm sure.
You do not need to dry as yet. Perhaps remove most of the standing water on the flat surfaces, but that's it for now.
After you have washed you can clay your car. I would suggest one of the two following kits that can be bought most anywhere automotive cleaning supplies are sold;
Mothers California Gold Clay Bar System - Comes with a Bottle Of Instant Detailer, A Yellow Clay Bar and a small bottle of Cleaner Wax.
Meguiar's Clay Bar Kit - Comes with a Bottle Of Quick Detailer and a White Clay Bar.
Have a few soft clean 100% cotton terry towels or micro fiber towels ready as well for wiping up.
In both cases the Instant or Quick Detailer will act as your lubricant for the clay bar! Clay is a soft mailable substance that will effectively and safely remove contamination such as rail dust, Industrial fallout etc. from your paint, glass, plastics etc. when used in a safe and as directed manner as below.
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Here we go...
Break your clay bar into two equal pieces. This way if you drop a piece of clay you have another to use! If you drop the clay..THROW IT AWAY! Do not use it.
Mold the clay in your hand to soften it and then mold it flat but not too flat between your palms. Spray a section of your hood (let's say a 1/4 of the hood) liberally with the Instant Detailer. LUBRICATION IS THE KEY! Use plenty of lube. Now pass the clay over the lubricated section using linear (back to forth) motion and LIGHT pressure to begin. Use a little more pressure as you understand a feel the action of the clay bar. You will feel and possibly hear the contamination being pulled from your paint up into the clay. It will feel rough at first, DO NOT PANIC and then it will smooth right out! When the feeling goes smooth and the clay bar passes over the section with ease, it's safe to assume that that area in now clean of debris. Look at the clay...filthy right?? Good..it's working. Wipe that area dry and thoroughly with a quality micro fiber towel or a 100% cotton soft terry towel.
It can be a little messy and runny but it wipes up very easily and will not stain your car or trim etc. If you do a nice job wiping up, it will save you the extra effort of having to re-wash the car or re-do the whole car with just the instant detailer and clean towel again!
Now run your hand over that section..it should be as smooth as glass and very shiny just by virtue of clean paint.
Now..turn the dirty side of the clay over to expose a cleaner side of clay. Don't worry, the dirt will turn in and be suspended high enough in the clay to let you work safely.
Spray another section of the hood and follow the same routine as above. Again..I cannot stress the importance of LOTS OF LUBE! If the clay feels like it is sticking to the paint, then you need more lubrication. After each area is complete, wipe it dry. You can do the same for your windows as well and even your trim.
I would suggest you do the whole car this time around! This way you have totally clean paint and a fresh "canvas". If you feel your clay is getting too dirty to use, then use the 2nd half that you broke off and set aside! My experience tells me that you should get by doing the whole car with 1/2 a bar, but use your good common sense and switch to a clean piece if you feel the need.
And YES..it might sound as though you are scratching your paint with the clay bar, but I say again..that with lots of lube and even pressure you will not be at risk.
Now...stand back and marvel at the results you just achieved with a simple piece of clay! You will probably not even feel the need to wax the car because the instant detailer will leave a great shine providing you did a nice job of wiping up after yourself. But you will wax...because I said so....lol
From this point on, you can follow up with the wax of your choice if you wish! Keep in mind that a clay bar will have removed any wax you had on your paint as well!
You do not need to clay every time you clean your car! I would think that once a year is fine.
Here's a video to watch:Clay Bar Usage