Case of the Mysterious Stain

Ok, maybe the stain isn't that mysterious. It's obvious that the previous owner spilled a couple of things in our pantry. And being as anal as I am, I want to paint absolutely everything in this house and that includes the pantry and its miscellaneous stains.

The problem is that no matter how many times I paint over the stains with my "Ultra Pure White" (there are many stories about this crappy paint) they pop back out the next day. I'm bringing out the big guns today. I'm going to try covering them with Kilz Stain Blocker, which I hope will cover as well as block. We shall see.