Cleaning a Female BNC Coax Connector?

The male and female parts of the connector are used together outdoors. 
There's no trouble disconnecting them, but they are both yellowed (rust?),

so the connection seems broken. The male part was easily dealt with by
some 
emery cloth. The female part has two cylinders, the outer one and another 
about 1/8" away. Cleaning in there is tricky with emery cloth. My smallest

file won't fit. Ideas?

-- 
            Wayne Watson (Watson Adventures, Prop., Nevada City, CA)

              (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
               Obz Site:  39° 15' 7" N, 121° 2' 32" W, 2700 feet

                     Web Page: <www.speckledwithstars.net/>