Noun. Can, as in “tin of soup.” Adjective form “tinned” also common Thanks to Ellen Magenheim.”How happy are the girls on the cocoa tin…” (John Ashbery, “A Sweet Place,” poem published in the New Yorker, October 28, 2002)”/[Gabrielle Hamilton] describes foraging in her mother’s pantry — which her father had not cleaned out, “the way a griever won’t empty the clothes closet of the deceased spouse” — and learning to improvise meals out of canned sardines and tinned asparagus.” (Michiko Kakutani, New York Times, February 25, 2011. Note: Kakutani’s use of both “canned” and “tinned” is a perfect example of the awkward reach for a synonym that Fowler’s Modern English Usage derides as “elegant variation.”)
notoneoffbritishisms.com 
Hershey’s cocoa used to come in a tin with a metal lid. Danish butter cookies come in a tin, with a lid that opens and closes.
I grew up (in the US) hearing “tin” for metal boxes with lids, such as those Danish butter cookies, and “can” for sealed metal cylinders of vegetables and fruit, etc. More recently, however, when I started hearing the expression “It did what it says on the tin” (and variations thereof) in UK TV shows, I struck me as foreign and novel. Instead, we’ve been saying something like “It worked as advertised.”
“It does exactly what it says on the tin” is a ‘no-nonsense’ phrase from an advertising campaign in the UK for Ronseal timber-treatment products such as http://www.youtube.com/watch?v=PXznmGz2fy4 which entered the vernacular in a more metaphorical sense but hasn’t the same cultural resonance abroad. For general use, “tin cans” or sometimes “tins” (as in “a tin of Coke”) strikes some British 18-year-olds who I employ as strange when they hear it, and certainly “can” is the preferred usage nowadays for these and cans of baked beans, given that they’re made of steel or alumin(i)um. I’d say it’s still widespread for luxury cookies (as in a biscuit tin) as it appears it was for tins of Hershey’s cocoa in the US and for baking tins and cake tins as bakeware.
“Tin” short for “tin can” is interchangeable for “Can” i.e. as in “a can of coke” or “a can of beans”. It probably arrived as an americanism, typically for products originating in the US, i.e. coca cola.
Canned drinks, but tinned food (including soup).
My father once bamboozled me when I was young with the phrase, “We eat all we can, and what we can’t we can.”
Now you’ve opened a tin of worms! (No, that is absolutely not BrE.)