On 15 June, 01:19, Frank Erskine wrote:

At school in the (very) late 50s *"Archie" Campbell had us believe
that "tinplate" was "tinned sheet iron".

I'm near Newport and Pontypool. Two towns that became rich on sheet
iron, first japanned with Pontypool japan (an asphalt lacquer) and
then learning how to tin it, with or without the lacquer. This
tinplate was made of iron for a very long time before it became a
cheap ductile steel.

Although not quite the 50s, unless you're a century older than you
appear.