Actually, wouldn’t canned milk spoil?
My mother used to use canned evaporated milk in her coffee.
She kept it in the fridge, but for a whole week she kept getting upset stomachs and severe diarhea (I CANNOT spell that damn word!) and couldn’t figure out what was causing it.
Later that week, she was taking the lid off the can to wash it before recycling, and found it full of green mold-not caramel!
Since it was probably sitting on the grocer’s shelf for a zillion weeks before she bought it, I doubt it. It’s not refrigerated at the store and need not be refrigerated at home. I do keep mine in the refrigerator, because I want it cold when I use it in my cereal (instead of milk). I have cans in there a couple of months old. Apparently your mother bought some stuff there was a zillion zillion weeks old. (How much is that in Britishspeak?)
Yes, see this link http://www.taunton.com/fc/features/basics/issue38milk.htm.
Wait, “condensed” and “evaporated” mean the same thing, that water has been removed. The various levels are merely marketing terms.
Anyway, we have established to my satisfaction that butterscotch is really just a kind of caramel, albeit perhaps an atypical toffee-like caramel.
They do by themselves, but they have different meanings as applied to canned milk, whether you refer to them as “marketing terms” or not.
Does anyone still eat caramels as a cure for the munchies?
In British English, we would use “too old”. We do not understand your need to exaggerate. 
Still doesn’t help us find Hokey-Pokey ice cream for sale in New York…
I assume it was opened then. It should be fine in a sealed tin, but once its cracked open, you’re inviting a slew of bacteria in. Same thing happens with my tinned tomatoes. Once I open them, they don’t last terribly long in the fridge…
when you retort a can a of condensed milk you are making what Latin American people refer to as dulce-de-leche. It is a fine example of the Maillard reaction pathways and does indeed taste a bit like caramel. The basics of it involves the reaction of carbohydrates and amino acids (probably lactose and casein in this case) to yield brown products. This same reaction pathway is how a steak becomes cooked.
BTW I dont think there is a standard of identity (at least not that i could locate in the CFR) so you can pretty much call anything butterscotch and not be incorrect. <–could be wrong on that though?
I think the fact that I understood all of this is a testament to the FoodTV Network and Alton Brown in particular!