Code P0411 secondary air flow check valve

I recently replaced the exhaust manifold catalytic converter on my truck. While doing so I had to move the secondary air flow check valve so I had room to pull the manifold. When I disconnected the hose that leads to the actual secondary air pump there was no carbon build up on the exhaust side of the check valve yet where the check valve attaches to the manifold it had carbon buildup on both ports going to the valve. I am now getting the P0411 code for the check valve. I read on the Trailblazer side of this site of a way to clean the manifold port leading to the check valve where the gasket goes between the manifold and the valve. Would I use a soft small bristle brush to clean the 2 ports and how do I follow the cleaning course up into the manifold if I can? Is it possible to clean the check valve from the manifold port side also?