There is some silver in those Crystal Oscillators. Acquire large batches. PIC 1.
Resistors toss. But sometimes crack the edges connections of older ones there has been gold plate.
Never find enough gold to process them though, been a waste of time searching. Pic 2.
Metalized Film Polyester capacitors, have some minimal silver.
I would suggest if saving these and processing, do it in very large batches.
Silver is minimal as far as I know. Saw a youtube from Asia, some silver present. Pic 3.
Personally I don't chase these, however if a person or company can acquire loads and process huge lots its possible to benefit from Pic 1 and 3.
Resistors have some other minerals in them don't think the small time refiner can get any benefit from them.