I'm just curious about octane boosters that you can add to your fuel tank. From what I see online, they will leave a fine light brown residue all over the spark plugs, after adding an octane boost adative to your fuel tank.
If the spark plugs are covered in a light brown residue would the cylinders and values also be covered in the light brown residue? How about the exhaust?
What is that residue and what effect does that have on the life of the parts?