On the UK Vintage radio forum, the chaps sometimes revive old capacitors by under-running them for a period, so that they regain their electrolytic surfaces.
Anyone remember Hunt's condensers?
All good stuff, but I'm about to find out if a tuner/amp that has been sitting in storage for 7 years, still works. It was a good amp - should be, I can hardly lift it, presumably cos of the transformer. Real amps come out of kit like that.