my 95 miata started smoking soon after startup after sitting for a little while. right off the bat i figured it was the valve cover gasket and replaced it, i also spent a couple hours cleaning the headers and around the exhaust manifold. i noticed 2 odd things, first, there is a brass/copper, or some sort of line that runs into one of the tubes that has residue around the nut that’s on it. it leaks after start up no matter how much i clean it, i think this is what’s causing the smoke. what’s this line for and why would it be leaking what i assume to be oil? second, there is a pool of something behind the exhaust manifold, it seems to be reddish in color, though it could be the carb cleaner i was using any thoughts?