Detailing clay is a substance that is designed to remove bonded contaminants from paint, leaving the paint smooth as glass
Allowing easier and more fruitful applications of polishes, glazes, sealants and waxes.
Detailing Clay is wiped gently across the paint which needs to be lubricated with a lubricant such as a Clay lube spray.
These bonded contaminates are hard to see, so after washing your paintwork looks clean.
However, if you gently run your fingers across the paintwork you may feel that the paintwork feels rough - a bit like stubble in a way.
This roughness, grittiness that you are feeling is the bonded contaminants in the paint.
Examples of bonded contaminants are:
and there are many others as well which your car is subjected to on a regular basis.