[Arran]

Mike;
That can be a concern, especially with Japanese pots, but the ones I was dealing with were used in 1930s and 40s Canadian made battery sets, and the resistive elements in those seem to hold up to the common solvents, in those days they used to spray pots and switches with carbon tetrachloride. Most of them also had no opening behind the terminals, so you couldn't easily spray anything into theme. My biggest headache is when a radio fell victim to the control replacement racket that was common in the 1950s and 60s, where they would replace a perfectly good control because it was dirty. The "magic one control fits all", replacements often didn't very well, or were installed crudely, though this was more the case with AC or AC/DC sets then battery sets.
Regards
Arran