My suggestion is to use the professional contact cleaner/conditioner made by CAIG. It is called Deoxit (I use PRO gold to condition, after using standard Deoxit to clean the contacts) I recommend it for any electronic/audio service work involving open type (dry) contacts.

It is what I use to clean and restore many electronic items, including 1950's -1970's vintage ham radio equipment.

It is not cheap...but works super.
It is recommended by many PRO repair shops.

Just a suggestion for the future....
Lee S.