Using acid and fire to get gold out of circuit boards

BBC science show Bang Goes the Theory goes all out to extract gold from old circuit boards.

Host Jem Stansfield uses acid and high heat to extract the precious metal.

One of gold's technological uses is for interconnections within semiconductor chips. According to the World Gold Council, gold has a unique mix of features that makes it useful for circuitry: better bonding properties, good corrosion resistance and high electrical conductivity.