But a few of them show negative voltages, such as -0.02 volts.... since it has a (-) value does that mean it is bad?
Not really, down that low I wouldn't worry about it. A simple quick test is to use the ohms test method. (Use lowest range)
The OHMs range generates a fixed voltage / current to calculate resistance. Connect +/- to the capacitor. You should see a
small "kick" (maybe), starting at around 0ohm then, then the resistance increases as the capacitor charges. Once it has
settled, reverse the probes. You should now see a big "kick" and the same process, starting from a negative value.
This indicates that the capacitor is probably OK. It's an old quick test method.
... a small amount of voltage and has to be discharged, I do it by touching the leads with two speaker terminals ....
Is that a safe way to discharge?
If you don't care what happens to the speaker, you'll probably get away with it, but it's not much effort to do it properly !
Make up a discharge kit. Solder
say 6" leads to a
say 1ohm-10ohm 1W-10W resistor (or make a couple different ones)
Solder
say 2-3" stiff wires to the ends (if you have old probes, even better). Heat shrink all exposed and soldered parts.
That way you always have a safe discharge set. Note: Always calculate how much power the resistor may need to dissipate !!