Battery Chamber is not connecting to new Battery.

Nikon D90, new battery, battery chamber is not connecting and won't 'accept' the newly charged battery or new battery. I think something is the matter with the chamber. Does anyone know how to clean? The three prongs at the bottom of the chamber are intact and seem to be working. The small circles at the bottom of the chamber seem clear of debris, dust, although there seems to be a group of circles that are silver and some that look bronze. Not sure if that is normal or not. Any ideas or where to get fixed?