I would remove all the rocker arms and clean them also you can use a brush and clean the head , diesel fuel will work good but it will wash it down to the the oil pan . Then you will have to remove the oil pan and clean it all out and when in the oil pan you can replace the oil pump because it has been pumping all that old oil and I would think it is worn pretty bad . How many miles on your XJ ?
DON"T start scraping it off
Youv'e had this xj for years and your just seeing this?
Good catch RCP.
Everyone should shine a flashlight into the oil filler hole when they get a "new to them" vehicle. Maybe before they buy it...
It's been running this long with low oil If you hadn't pulled the valve cover, you'd be happily driving the crap out of it, right?