What type of axial capacitor is silver with transparent ends
They sound like polystyrene capacitors: -



If they are I'd hang on to them - they are generally quite a stable type of cap and mostly they are better than 5% tolerance (I think that's what the J is in your question). Not as good a dielectric as C0G/NP0 but not far off. Usable in good quality filters for audio and signals.