Car wax is used after washing and polishing to add a layer of shine to the car as well as a layer of protection. It is a type of paint sealant. If there is any dirt or stains on the paint, then the wax will seal it on the car. Wax will protect your car from UV rays and will prevent pollution and other dust from damaging your car. It also minimizes the moisture that comes into contact with the paint as water causes corrosion.