A few months ago I made Ruhlman's Olive Oil Duck Confit. The duck has been eaten, but I left the oil in my dutch oven and kept it in the refrigerator to hopefully use again for another batch. So I've got 2 layers; the bottom layer is darkish brown with a jello-like consistency, and the olive oil is solidified in a harder layer on top. I'm not sure if the bottom layer is straight duck fat, as the duck fat that I usually see is not this dark. Everything smells fine and even tastes fine. Is this safe to use again?