I like these Jonard burnishing tools for relay contacts and telegraph key contacts:
https://www.amazon.com/Jonard-OB-1-Burnisher-Insulated-Thickness/dp/B006C47JOI/
Close the contact on the blade of the tool and pull out. I follow-up with a little Deoxit D5 rubbed on from a piece of paper.
Steve WD8DAS
sbjohnston@aol.com
http://www.wd8das.net/
http://af4k-crystals.com
--------------------------------------------------------------------
Radio is your best entertainment value.
--------------------------------------------------------------------