FX: When it comes to Silver, Gold or copper plating on equipment, I was in my earlier years under the myth "Shinny" was better.
Then having done the removed to much and damaged the plating, I have changed my thinking somewhat.
Every time you clean and make "pretty" you remove material. I now rethink cleaning a entire piece and just "touch-up" the points where the connections are critical...
I'm guessing your cleaning an antenna coil or roller inductor?
The cleaning of any type of roller coil you have to remember the core can be contaminated also with the cleaning agent. The case in point ceramic or Mica will retain some of this regardless of how much rinsing you do.
Most cleaning agents like TarnX, contain acid, and even with through rinsing some of it remains and can continue "eating" away material overtime.
I have used good old Isopropyl Alcohol and Qtips more times than anything of late. then burnish the connection ends lightly with a Scotch brite pad or 00 steel wool...I only use steel wool when the component is out of the equipment due to leaving anything inside that may harm other connection points...clean dry air can remove 99% of left overs....
More later...gotta go!
All the Best
Gary