Not charging, Charger light Green

Hi guys!!

Got a Macbook (mid 2007 model) that will not charge. It works off the power cord but cant charge the battery.

I charged the battery in another macbook and it works fine and holds charge. I also tried a different magsafe power adapter and same thing.

When plugged it, light turns GREEN and stays lit but in Max OSX says "Not Charging".

Tried a SMC reset no luck..

Any advice what it could be? Im looking at the DC-IN port but anyway i can narrow it down to that specifically?

Some say to clean the connector port, any recommendations with what? Qtip and nail remover?

Thanks!