Many years ago, I can remember trying to find ash trays that were not badly pitted so they could be taken apart in order to replate the tray part. We would then find some rivets to put them back together. Now there is a really nice reproduction available of the '65-66 and '67 model Mustang Ashtray!
They both look very nice with the correct plating and rivets. If you want to get really picky, like me, you may want to remove the front cover to paint it. You could probably do just fine though by painting the cover while it is still attached.
Another really interesting note that I just never paid any attention to-the '67 Mustang ash tray is different from the '68 model. You cannot use the '67 on the '68 or vice versa. Maybe we will see the '68 model soon.