Vinegar's acidity is what makes it such a good cleaner. Because vinegar is so acidic, it can counteract some icky buildups. It can dissolve away soap scum, brines left by hard water, and glue left behind by stickers.
The PCV valve is a control device which sends partially burned gases that come from the engine's crankcase to the combustion chamber. Its name, PCV means Positive Crankcase Ventilation and is one of the oldest and most used emission control devices.he PCV valve is a control device which sends partially burned gases that come from the engine's crankcase to the combustion chamber. Its name, PCV means Positive Crankcase Ventilation and is one of the oldest and most used emission control devices.
the PCV is supposed to allow enough vacuum to the valve cover to cause a slight negative pressure in the crank case and suck out the blow by into the intake manifold to be burnt. the foam pad in the breather is to filter  the air that is being drawn into the crank case by manifold vacuum.