I think my peanut butter is turning gray

This is a little alarming, but not enough so that I have stopped eating it. Question: who brings home a partially used tub of skippy on a 5 hour flight from Maui to San Jose because she can't bear to throw it away so full? Answer: I do. And after only a month, it seems to be turning on me. I noticed the other day as I was artfully slathering it onto my freshly toasted home pride slices that it didn't look as brown as it should, but chalked it up to the lighting in our breakroom. Now, there's no mistaking it. This peanut butter is getting stale. However, I am a pro at ingesting things past their prime. Two week old spaghetti? No problem. Three year old frozen hamburger meat? Down the hatch! Pizza left out on top of a heater for two days? Mm Mm good! My stomach, surprisingly, takes it all like a pro and hardly complains. I can either take this as a testament to how much my body wants me to be a sack of lard, or I can put a positive spin on it and say that my digestive system is much more highly evolved than most. In a hundred years, I may be the mother of the next generation of superbeings capable of feeding on steel and cardboard. You heard it here first.