. this picture is of one of the last buckles I found just after a quick wash to remove the loose dirt . there is a dark green crusty layer that is still stubborn to remove and after almost a week it starts to crack and flake off . I removed the rest of the crusty layer with a wooden tooth pick to see a slick mottled color patina , ideally you want a slick looking patina on brass and copper . then I used a soft bristle brush to remove any tiny amount of dirt and then coated with a generous layer of Ren-wax let dry out completely (it gets whitish dull hazy look when its dry) then I buff it vigorously with the same nylon brush to bring out a nice sheen like this picture shows. 