Radio cleaning and pre-emptive cap. repair?

I would just replace it. That would be an electrolytic, capacity is not that critical, you want at least but not less in capacitance, and at least the rated operating voltage, Last I knew, Mouser Electronics would fill small orders, and has always been helpful.
Yes they still accept small orders - just ordered some terminals from them yesterday.
If a replacement can be put in, that sounds like the better route to go.
It looks like there may be good access to the board with the bottom removed.