Pin oxidization

I’m having trouble with poor contact on some of the pins/sockets of the connector on the rear of the CRT in a monitor. As these age with multiple heat/cool cycles and humidity, problems with oxides or other compounds on the metals emerge.
Most of these are not soluble in electrical spray cleaners… I have used propyl alcohol on a brush for the pins but the socket holes are too fine.
I know this used to happen more often in the days of valve amplifiers. Any suggestions please?