I recently bought a clay "ollo" (bean pot) from Mexico. I cooked a batch of beans and noticed a silverish film on the inside of the pot. I was able to scrub it off. I'm guessing this is a result of lead paint? Is this the case and do I need to worry/? I suppose I shouldn't use the pot but boy, the beans sure taste good cooked in it. Is there a way to delead this pot or is it something else that I should worry about?