[codefox1]

There's no good way to test a capacitor in circuit when it is shunted with an inductor or resistor. Modern digital hand held meters that read capacitors do not apply significant voltage to prove them good or not, but can mostly show how values have drifted up or if capacitor is completely shorted or open. Old time bridge contraptions and capacitor checkers can test somewhat the condition under load and even re-form those ticking time bomb electrolytics. I have an old Eico 950B that can drill down pretty well on a bad part. I use it pretty much for curiosity purposes.

If you have an antique radio and want to restore it, best just replace all the capacitors, and while you're at it, all the carbon resistors as they will also have drifted up , and are prone to temperature variations after all those years. Makes a huge difference when you finish up and align the set.