Best way to clean up these connector sockets?

[ridgy]

This is a NASA clipper depth, discovered during winter checks, works but quite manky.

 

[Refueler]

All you can do is Contact cleaner ... or Ethanol .... liberally apply to plug ... and insert / pull out repeated .. applying cleaner repeatedly .. wipe away crap as it comes out.

 

[justanothersailboat]

You can get glassfibre pencils from electronics suppliers, or use a rolled bit of very fine wet'n'dry paper to clean up those outer connector rings... but... that will reduce any remaining corrosion resistance that might be left from plating on the connector surface.

 

[Alex_Blackwood]

This is a NASA clipper depth, discovered during winter checks, works but quite manky.

If you can get to the back of them? Then replace them. They are available, the 5 pin one is a 5pin 180 deg. socket.

 

[mogmog2]

And when you've done as much removal as you're going to, smear with a dielectric grease ideally, but Vaseline is better than nothing. Dielectric Grease: What it is & How to use it | Electrical4U.