bird droppings seem to be more of a problem nowadays, this is probably down to manufactures using water based products, once you've cleaned it off, your next step it to remove a little of the laquer coat, this is where the poo has etched in, a fine polish should do this, frecla have good compounds for this. then you need to apply a wax coat.
as for selants like the car lack, amazing glaze diamond brite an all its other guises, this coating is easily removed, even a good traffic film remover, or fairy liquid will remove this coating. this is why they tell you to use warm water, soft sponge and a car shampoo.
ps i own part of a family run body shop, so if people have anymore questions about dents paint polishing and stuff just ask away
jake
