[Auf los!]

OK, here's a weird one. I am getting the smell of vinegar coming from my dash vents. It's not the smell of mold or mildew, it really smells like a nice balsamic vinaigrette! I can smell it even with the top down. Is this oddity in anyone's experience? What could it be?

I squirted some "Odoban" (like Febreeze, but stronger) down the vents, and leaving the car top down in the garage overnite. Hafta see if it makes a difference in the morning. Cabin/pollen filter only a year old. Could it be battery acid I'm smelling??