A FSogol Family Christmas tradition repeated every year without fail

I make two tone fudge (Chocolate and butterscotch) to enjoy and to give away over the Holidays.
It calls for 2 cups of evaporated milk.
Evaporated milk comes in 12 oz cans.
I use 16 oz and am left with 8 oz.
I ask Mrs FSogol, "Should I dump this, or do you want it for something?"
Mrs Fsogol replies, "Don't dump it, it is good in coffee."
FSogol, "Are you sure, it always sits in the fridge?"
Mrs FSogol, "Yes, I'll use it. Put it by the milk."
Mid-March while investigating a strange smell in the fridge, we discover 8 oz of rancid evaporated milk.