Lifter galley paint

I used to work with a guy who was adamant that non-detergent motor oil was the best. His evidence? He would proudly show anyone how he could pull the dipstick and the oil looked as good as the day he put it in.

He was a mechanical engineer, so you can imagine my difficulty when I tried to explain to him that the oil is supposed to get 'dirty' so it carries with it the combustion byproduct when you change the oil, rather than leaving it in the engine, and he couldn't grasp that.