Tin

You may be looking for the type of container.

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

Tin was a highly bendable material. (TV: The Ark in Space) The First Doctor noted that a spaceship made of tin would not be very resistant to damage. (TV: Galaxy 4)

Tin foil could be used to wrap chocolate (TV: Planet of the Dead) or make hats, (AUDIO: Blood of the Daleks) which could be used to protect their wearers from psychic energy. (TV: Dream-Eaters)

History

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 Robert 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)

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)

Metaphorical tin

Things made of metal sometimes were referred to as being "tin" as a form of disparagement.

Despite not being made of tin, K9 was occasionally referred to as a "tin dog" or "tin animal". (TV: The Creature from the Pit, School Reunion)

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

The Master, despite his standing alliance with the Daleks, privately called them "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)