What I would do is connect an incandescent bulb across the terminal of the cap and wait for the bulb to light up and then go dead. the resistance is very low and thus most of the changes get dissipated and the visual thing makes my morale boost to touch the terminals bare hand. Surprised to see none has replied with this. Is there any safety issue, I don't know for sure. But works for me!
I'd thought of something on those lines but the o/p didnt say the voltage across the cap, connecting a 12v bulb to a cap with 400v across it would have given him a surprise, kapow.
The problem I have with this thread is that post #1 said the device was a ROUTER.
I will have London to a brick that this thing has a universal motor and ergo, there is no need for a 'starting' or 'power factor correction' capacitor. So what actually are we talking about???. Without a picture what can be said that makes sense??
Hmm, shows how wrong you can get it, I thought router as in internet router.
If its a woodwork router then yes its probably a class x suppression cap.
Pic please.