Anything you could do would involve some sort of coating. I am not aware of any clear coats that would dull it down, so you'd be looking at painting it which may void the product warranty. I will say this though ... at it weathers some of the shininess will diminish.
Todd Miller
2017-07-05 21:06:27.000000
I have just installed a Galvalum metal roof it is very reflective anything I can do to calm it down