What to do with Oil leaks by manifold?

If you are talking about the EXHAUST manifold then most of the time it's the valve cover gasket that is leaking oil. REPLACE VALVE COVER GASKETS.

If you are talking about the intake manifold then it has 2 rubber gaskets in the front and rear of it that leak oil real bad. If oil is on the left are right top sides of the intake manifold were the valve covers are then it will be the valve cover gaskets that are leaking oil.