Music studio recording gear etc.

I found a older Concert lighting mixer a week ago. It looked like someone took a axe to its rear panel.
So I took it apart for the Ali fascia & inbuilt transformer & misc brass.



Then I looked for silver contacts on the switches & there was some, tiny, but theres about 40 switches along with 30 odd sliding rheostats to vary the light brightness.

That got me thinking... Studio gear should be made almost bulletproof & of the highest quality.
So I expect theres a good amount of gold & silver in the contacts on these boards, along with the multitude of switches they use.

Does anyone know what sorts of metals & amounts to expect from disused recording gear?

only your refiner will know for sure ; )