[Tubesforme]

I purchased a Model 70 that was supposedly completely restored. However I was told that when tuning stations there was a scratching sound. There sure is when the plates are close to fully meshed. I checked the tuning capacitor and am positive that there is an area where there is what appears to be a super thin metal coating that is flaking off the plates. I have been in the business for over 50 years and have never burned a tuning capacitor. I know that it must be totally disconnected from the circuits and I once read you could use the HV from the chassis to burn this coating off. Has anyone ever attempted this and if so would you please instruct me in the correct method. I do not have a separate DC supply and I doubt if you would use AC. many thanks to all of the professional Philco help on this site.