once dissasembled i tried several ideas to do this, first i realized that the signs were solid aluminium inserts, that means that you can not remove them, but they are easy to mask as there is a separate thing from the fascia
so first i removed old paint chemically, but the base surface is too flat and i intend to reproduce some rugosity, so i sand blasted it protecting the signs
i painted and checked with the actual tone, were four layers