Rodent droppings on cast-iron frying pan
If it's cast iron, and you're really paranoid about it, just stick it in the oven, run a clean cycle, then re-season. Cast iron can withstand stupidly large amounts of heat: in traditional Chinese cookery, woks are cleaned by building a big fire, and throwing them in...When the fire burns out, you dig out your wok, re-season, and you're back in business.

If it's stainless, just stick it in the dishwasher.