S.S.
Fridge. Always.
But we never ever use margarine. We used to have a rental property and the last guy who lived there had a fridge that died. He put it out on the back porch and didn't clean it out. When he was evicted several months later, we had to clean it out (NASTY!) and the only thing we could recognize was the margarine. It was still in the wrapper, still yellow, and still in a rectangle shape.
I decided at that point that it must only be a few chemicals away from plastic and it was better to have all the fat and cholesterol from butter.