"picked up a tea caddy"

A tea caddy is a box or jar used to store tea.  Tea bags did not come properly into existence until the 1950s (Tetley introduced them in the UK in 1953), so prior to this it was necessary to have a receptacle to store the leaves.  Tea was also more expensive in the past, and correspondingly tea caddies over the centuries could themselves be highly valuable and decorative items.  It is likely, however, that the tea caddies referred to here are common tin varieties.  Despite being much cheaper, they were often charmingly decorated, for example with contemporary logos and advertisements for brands of tea.