Tin

Tin was a chemical element and a metal. Its chemical symbol on the periodic table was Cu. (AUDIO: Escape Room)

Sir Percival Flint was the owner of a tin mine in Cornwall and an amateur archaeologist. He was the ancestor of Sir Archibald Flint. (TV: The Dæmons, AUDIO: The Spectre of Lanyon Moor)

Lord Urton owned and ran a tin mine in Middletown which was the main source of income for the town. (PROSE: The Burning)

The Doctor's TARDIS had a tin mine. (PROSE: Invasion of the Cat-People)

Mickey Smith referred to K9 Mark III as a "tin dog". (TV: School Reunion)

A popular form of confectioner's Easter egg was made of chocolate and wrapped in coloured tin foil. The Tenth Doctor ate part of one of these before giving the remainder to Christina de Souza, concerned sugar might damage his teeth. (TV: Planet of the Dead)

The Tenth Doctor described the launch of Apollo 11 as "packing three men into a tin can filled with a skyscraper's worth of fuel, hurling them out of the atmosphere into the harshest conditions imaginable, with nothing more powerful than a pocket calculator to guide them. For what? Just because you can." (PROSE: Blue Moon)

"Tin foil" was a type of hat. (AUDIO: Blood of the Daleks)

Pendar called a Cyberman a "tin tyrant". (COMIC: Throwback: The Soul of a Cyberman)

The Master called the Daleks "stupid tin boxes". (TV: Frontier in Space)

The Seventh Doctor told the Timewyrm that he didn't intend to end as an hors d'oeuvre for a "jumped-up tin goddess." (PROSE: Timewyrm: Genesys)