I’m willing to admit my dark kitchen secret because I know you’ve done it too. I, on occasion, leave food in its open tin can and pop it back in the fridge. Not proud of it. It happened just last week. I was done baking for the day and found myself with half a can of pumpkin puree left over. I was already mentally done for the day, and in childlike resistance, I just didn’t really feel like transferring the gloopy pumpkin substance into plastic. “It’s in a container already!” I reasoned. But I had heard that storing food in open tins cans is never good, so I set out to investigate exactly why. After scouring the internet for far longer than it would have taken me to just put my leftover pumpkin in plasticware and get on with my life, I found an official vote of confidence for my occasional…