Shaping the light is how you light metal. Just throwing light on a metal object will produce the desired effect. This is what you see a lot of on ebay and other websites where people are selling metal objects (Top).
Check my Yamaha YTR-734 Silver Trumpet, which I pulled out and started playing again. After cleaning it up I didn't want to waste not preserving this for myself.
I have two hotshoe Nikon Speedlights (1 SB900 & 1 SB800) lighting the trumpet. They are setup like a typical copy stand photo shoot. Works great for objects other than metal. Perfect for copying flat artwork and books.
By removing the blue fabric the white table wrap the light around the metal and give it more shape (Right).
However, my recommendation is Tent Lighting. When you wrap an object with light all around it you get much better results, (Below).
I think you might do a better job of selling this trumpet on ebay with lighting like this than the light above.
Notice how in the bell the blue fabric is reflected (Right). If you look really close you will see just a little black spec. This is the camera peaking thought the front panel.
Maybe you want something in between the top photo and light wrapped all around the object. Instead of tent lighting just use white foam board and cut it into different shapes. You can then put a black sheet out of the photo but blocking light. Then just place the strips of white foam board to place you want to add white verses the black
Slowly you can give different looks. Use different color foam board and you can add color to the reflections like the blue fabric is doing here, but just put it outside the view of the camera but in the reflection of the metal.
Rather than me showing you everything, try shooting something yourself and see what works for you.