At risk of kicking in an open door: have you tried using contact spray? I own a can of contact cleaner 390 by Kontakt Chemie (I'm sure other brands work similar

At risk of kicking in an open door: have you tried using contact spray? I own a can of contact cleaner 390 by Kontakt Chemie (I'm sure other brands work similarly effectively) and that stuff is basically magic for intermittent contacts. So far I've used it to repair a buttload of wonky plugs, corroded battery contacts, as well as all the switches and volume knobs on my 40 year old amplifier. the volume knob still amazes me most. it went from an awful crackly mess to perfectly smooth and it still is perfect 5 years later. Anyways long story short: give contact spray a try. Worst case the contacts are deformed too badly and it wont work.