First lets start by explaining "What is a Claybar?" , a Claybar is a malleable substance that is made up of a very soft clay. There are two main types of automotive claybars, the first one is a claybar that is a soft malleable putty like substance and the second one is a synthetic claybar which in most cases are clay mitts. It is basically the clay substances on a mitt, but can be used multiple times and last longer than a traditional claybar. They both will do the same thing, but traditional claybars are work better with heavily contaminated vehicles.
A claybar is used after the car has received a deep cleaning on the exterior, but after the wash there are still embedded containments in the paint that have built up over the years. Sometimes the contaminates can also be iron contaminants which aren't removed with a claybar, but instead with a liquid called an iron remover. After you have removed the iron contaminates you will start the claybar process. You will need a liquid with a lot of lubrication like a spray wax or a quick detailer, you can even use a foam cannon soap that has a lot of lubrication.
To start the claybar process you will use your lubrication of choice and spray it on to the vehicle . You will then start to glide the claybar across the paint in straight motions. Make sure you are using enough spray wax or detailer to prevent the claybar from catching on to the paint and marring the paint. The claybar should glide across the paint in straight motions and you should feel the paint getting smoother.
After you have clayed the whole vehicle you will wash off the excess spray wax and/or detailer. Next you will polish the vehicle and apply a sealant or coating. You can also skip the polishing step and seal up the paint with polymer sealant or a spray sealant, or any type of paint protection of your choice. It is recommended that the protection should last 6 months or more.