We all already know Dragon Scales can be dyed... so why not have a slight hue or tint to dragon scales in general? either normal colors (Bronze-ish colored for Sandstone and Bronze, and even up to a Shiny silver color for Mithril scales...)
or just add the hue when a scale is dyed? I'm not saying turn a black dragon into a completely 100% changed silver dragon by dying the scales, I'm just saying a very very slight highlight seeming where the scales would essentially be... like an undertone sorta? That would barely if at all affect how your dragon looks, but it gives Dragon Scale Dyes a reason to be there
so if you add green to your scales you see maybe a reflective green in the sunlight or highlights in different places than your highlights(If you have them)
I've talked it over in game a bit and guildies/friends tend to like it.. so I figured I'd bring it here ^.^