Well paint Protection is sort of like the teflon coating on your frying pan. Makes it real easy to 'wipe' clean but if you scratch it off with a knife and damage the teflon coating then food will stick to the surface easily and make it harder to clean. When you use a cutting agent and some polish's they actually have a very fine sand like material in it which actually takes a fine layer of coating off, hence making it look really nice and shiny So thats why they recommend that you dont polish cars with paint protection on it and just give it a good wash with lots of water and a soft sponge/cloth with soap