In this video, I actually experience bird poop etching damage on a unprotected panel. I go through the same process that I did in my first video on this subject and repair the damage.
The main thing that you should take from this video is the importance of clay in the process of removing this damage as well as the importance of addressing this damage very quickly. Etching begins immediately once any undesirable substance lands on your clear coat or paint and the longer that you wait before addressing it, the harder it will be to remove. Hard water stains, tree sap and bird droppings are the most wicked of substances to leave on your clear coat or paint, especially if your clear coat or paint is not swirl free. If your clear coat or paint is swirled up, then the etching damage will penetrate twice as fast and become more permanent much quicker.
Clay pulls the etching damage out of the clear coat or paint WITHOUT removing any clear coat provided you are using the lightest type of clay, which I refer to as consumer grade clay. That's why you always start with clay first. The object is to remove as much of the damage as possible first, so that you don't have to remove as much clear coat or paint. After all, there is only so much clear coat and paint on your car.