Caroline it actually isn't dried oil it looks like when a light bulb has blown out but yet it hasn't? Oh, I just thought of the perfect comparison depending I guess on how old someone may be, it looks like the old flash bulbs after you took the picture. But I really want to know about the little piece that broke off if it is necessary or not. I did read the manual but it doesn't refer to it at all, so don't know how important it may be. Do you happen to have a 401A?