Thats not easy !! Scratch test is best but not always possible !! Spelter will have a silvery gray color,,brass a yellow gold and bronze a coppery red/brown !! But you have to scratch through the older surface to see whats underneath !! Usually a small scratch on the bottom where no one can see it will tell you !! Aged bronze has a beautiful coppery red glow to the worn areas !!
Kind of hard to explain but when you have seen the older bronzes its easy to know the difference !!
