Millions of set top boxes are taken out of service every year. Some can be re-deployed as a full unit by the content provider. Some can be used for parts to repair other units. Nevertheless, most need to be "put to bed" permanently. Units with hard drives can derive market value by removing, wiping, and testing the hard drive. This must be handled very carefully as the liability for data content on a STB can be onerous.
The remainder of the box can be easily recycled in the most environmentally friendly manner. We work with a number of R2 certified recycling partners who maintain huge shredder/sorter machines that grind up and spit out the base materials of the box separated by their unique elements. Copper goes in one bin, aluminum in another, plastics in still another. The bins are then sent to smelters who recycle this scrap into base metals and plastics.