Gold

Gold is a chemical element much prized by Humans.

Gold is also notable as a major weakness of Mondasian Cybermen. Owing to its non-corrossive nature, gold essentially choked their respiratory systems. Tthe glittergun, a weapon used during the Cyber-Wars fired gold dust at its targets to exploit this weakness.

Gold appeared to affect some varieties of Cybermen in the way thta silver affected werewolves. Gold coins or gold-tipped bullets fired at them had the same effect. (DW: Silver Nemesis)

Other weaknesses of Cybermen included solvents and excessive levels of radiation.

During a time period in which Cybermen had been reduced to small remnant groups wandering around the galaxy. One group tried to take revenge by making a desperate attempt to blow up the remnants of the planet Voga, a planetoid of pure gold that had wandered into the Sol system and become a moon of Jupiter. They hoped that this would disrupt their enemy's supply of the metal. (DW: Revenge of the Cybermen)