Doctor Who's latest outing Ascension of the Cybermen landed us in the the aftermath of the Great CyberWar, with the Doctor (Jodie Whittaker) and friends attempting to fight back against the Mondasian monsters who'd devastated a future Earth.
Though their efforts are ultimately unsuccessful – those pesky Cyber-drones! – the Time Lord's techniques used against her old opponents are actually tried-and-tested, having succeeded in felling the Cybermen on previous occasions.
For a race of 'unstoppable' killing machines, the Cybermen are actually susceptible to quite a few things, so here's a recap of all of their weaknesses – including some that were featured in the opening scenes of Ascension of the Cybermen and some that were mercifully forgotten...
"Cybermen are allergic to gold, right?" "I did hear that once."
Though Spandau Ballet's 1983 hit Gold might tell you that "you're indestructible", the Cybermen are anything but, with a particular vulnerability to the precious metal.
In Ascension of the Cybermen, the Doctor has rigged up a particle projector to release particles of gold into the air. This weakness was first established - as a rather convenient plot contrivance - in 1975 story Revenge of the Cybermen, which saw the monsters battling a race from Voga, the Planet of Gold.
Gold, we're told, chokes a Cyberman's respiratory systems, with a gold-tipped arrow or even the touch of a gold coin proving enough to disable them. Perhaps most memorable of all, the Fifth Doctor (Peter Davison) used the discarded gold badge of his companion Adric (Matthew Waterhouse) to clog the Cyber-Leader's chest unit in 1982's Earthshock.
"Emotions – love, pride, hate, fear! Have you no emotions, sir?"
As Graham (Bradley Walsh) explains to Ethan (Matt Carver), the Cybermen have suppressed all emotion and sensations of pain. If these feelings can be unsuppressed – using, say, a "neural inhibitor system" – then they'll experience the physical and emotional impact of the horrors inflicted upon them.
We first saw an enemy use the Cybermen's own subdued sensations against them in 1968 story The Invasion, wherein their former ally Tobias Vaughn (Kevin Stoney) drove them "mad" using an an emotion-enhancing device.
The Tenth Doctor (David Tennant) and friends were also able to disable the Cybermen's emotional inhibitors in 2006's The Age of Steel, while a burst of pure emotion – the love that Craig (James Corden) felt for his son Alfie) – was powerful enough to obliterate the cyborgs in 2011's Closing Time.
Though gold and their own emotions are perhaps the Cybermen's most well-known weaknesses, their first vulnerability as established in 1966 debut The Tenth Planet was radiation, with a squad of the cyborgs being overcome by emissions from the Z-bomb, a powerful weapon held at a space tracking station in Antarctica.
Even smaller radioactive rods are enough to fight back against the creatures.
If you thought falling prey to a gold coin was bad, 1967 story The Moonbase saw the Cybermen defeated by "Polly Cocktail" – a chemical mixture invented by the Doctor's companion Polly (Anneke Wills) which attacked the plastic components of the monsters' mechanisms. (Polly got the idea from how nail varnish remover dissolves nail polish, obviously.)
A blend of acetone, benzene, ether, propane and alcohol, this chemical combination was shot at the Cybermen using adapted fire extinguishers. Points for ingenuity if nothing else.
An EMP – a discharge of electromagnetic radiation – was used to cripple a Cyberman in The Age of Steel and to eject the Cyber-Planner from the Doctor's mind in 2013's Nightmare In Silver. (The Cyber-Planner was a mechanical strategist custom-built by the Cybermen to assist in their battle plans – a more primitive version of the Cyberium from The Haunting of Villa Diodati.)
Guns, bombs and even swords
Besides these more unusual means of defence, Cybermen have also been fought off using more conventional means over the years: they're vulnerable to certain energy weapons (including Dalek gun-sticks), plus good old man-made explosives / artillery weapons.
Even a sharp enough sword can pierce a Cyberman's armour (as seen in 2010's The Pandorica Opens).
It's a marvel, really, that the Great CyberWar went on for as long as it did...
Doctor Who continues on BBC One at 6:50pm next Sunday