I know literally nothing about how the Russians treated their aircraft.
In the RAF it was forbidden to alter the surface finish in any way, and instructions for the cleaning of the surfaces were detailed. Some senior figures, who effectively had a personal aircraft, may have bent this rule. Waxing or polishing was specifically forbidden because it both compromised the camouflage and permeated the surface making repairs a much larger undertaking. This is the most concise of the instructions for cleaning an RAF aircraft I have, others are more long winded and detailed.
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The Americans, at least some of them, waxed/polished their aircraft. I have heard from my old mucker Nigel Julian, who interviewed survivors of the 8th Air Force's 56th Fighter Group for his book(s) that several ground crews confessed to using various products, including automotive polishes, on their airframes.
To me all the images of aircraft in Russian service look well used. I'm sure they were well maintained and the original American finishes were tough enough, I don't see much chipping or evidence of touch ups. The repairs would have to be done with 'equivalent' Russian paints (like the over painting of the blue of the US star on the port wing of this model) and I don't see much evidence for it. I don't get the impression that they were too bothered about the finish of their aircraft.